Green Energy&Environment

Revolutionizing eco-environmental solutions through 3D printing: A strategic vision for future innovations

Xudong Guo, Bin He, Ligang Hu, Guibin Jiang

2026, 11(3): 591-602. doi: 10.1016/j.gee.2025.12.015

Abstract(114) HTML PDF

Abstract:
Three-dimensional (3D) printing technology is emerging as a transformative tool in eco-environmental research. It innovates environmental analysis technologies, augments environmental purification, alleviates environmental health risks, and fosters ecological sustainability. Nevertheless, most current applications of 3D printing in the eco-environmental domain remain largely confined to laboratory testing stages, with limited translation to large-scale and real-world deployment. In this viewpoint, we review recent progress and critical challenges within this field, while providing strategic perspectives for its future trajectory. We highlight the imperative to integrate cutting-edge 3D printing techniques into eco-environmental research, advance sustainable printing materials, and develop integrated multifunctional devices for environmental monitoring and remediation. Furthermore, we introduce a pioneering conceptual framework: self-sustaining composite artificial biosystems. Here we envision it as a bionic tree, a 3D-printed biohybrid construct that integrates an open microfluidic scaffold with engineered living materials to autonomously maintain biological activity through self-driven internal mass transport. While emulating key morphological and physiological features of natural plants, the bionic tree transcends its natural analogue by enabling synthetic biology-guided environmental remediation, CO₂ sequestration, and energy production. We provide an in-depth analysis of the rationale behind this concept, assess its technical feasibility, and present a developmental roadmap for this emerging research direction. Our insights are poised to amplify the contribution of 3D printing to the eco-environmental sector, thereby facilitating environmental pollution control and sustainable development.

Ammonia synthesis and cracking: Thermocatalytic versus electrochemical approaches

Xue Ding, Sze Xing Tan, Lili Zhang, Jiajian Gao

2026, 11(3): 603-629. doi: 10.1016/j.gee.2025.12.018

Abstract(123) HTML PDF

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Ammonia (NH₃) is a key chemical for agriculture, energy storage, and industrial processes. Its synthesis and cracking (decomposition) are pivotal for a sustainable energy future, particularly in the context of green energy transitions. Two major approaches for these processes are thermocatalysis and electrocatalysis, each with unique mechanisms, challenges, and advantages, as discussed in this review. Thermocatalysis is more mature but energy-intensive, while electrocatalysis promises lower energy consumption and compatibility with renewable energy sources. Electrochemical approach has the potential to eliminate carbon emissions if coupled with green electricity, whereas thermocatalysis is reliant on fossil fuels unless carbon capture is implemented. Thermocatalytic processes for ammonia are well-established at an industrial scale, whereas electrocatalytic systems require further technological development to match this capacity. In summary, thermocatalysis remains the dominant method for ammonia synthesis and cracking due to its industrial maturity. However, electrocatalysis offers a promising pathway toward sustainable and decentralized solutions, provided ongoing challenges in efficiency, stability, and scalability are addressed. Balancing these technologies will be crucial in transitioning to a low-carbon economy.

Transition metal dichalcogenide nanostructures: Synthesis and application in detection and removal of metal ion contaminants from water

Xinyue Xiang, Binqi He, Maiyong Zhu

2026, 11(3): 630-698. doi: 10.1016/j.gee.2026.01.005

Abstract(166) HTML PDF

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At present, global freshwater resources are severely lacking, and all life activities rely on freshwater resources. Industrial and domestic wastewater contains a large amount of toxic heavy metal ions and other toxic substances, which are not only harmful to human health but also cause significant damage to the environment. Therefore, it is necessary to detect and remove these metal ions. Although many technologies have been studied, there are still many deficiencies. At the same time, due to the vast proportion of the ocean on the earth, people hope that seawater resources can also be utilized by humans, and research on seawater desalination technology is being carried out. Capacitive deionization (CDI) technology has high desalination efficiency and no secondary pollution during the desalination process, and is therefore widely used. The core of these technologies lies in the materials used. Graphene-like materials, with their large specific surface area and numerous surface active sites, have been widely studied, especially transition metal dichalcogenides (TMDs) materials, which have excellent physical and chemical properties. This article mainly introduces the application of TMDs materials in the detection and removal of heavy metal ions in solutions and in CDI desalination, analyzes the advantages and disadvantages of the materials, and discusses the future development direction.

Recent progress of surface/interface modification of transition metal oxides for enhancing electrochemical energy storage and conversion activity

Zhiqiang Cui, Siqi Zhan, Rui Mei, Mengping Liu, Minglei Cao, Qin Wang, Yating Zhao, Rui Tong, Dongming Cai, Zhenghui Pan

2026, 11(3): 699-723. doi: 10.1016/j.gee.2025.12.013

Abstract(133) HTML PDF

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The electrochemical performance of transition metal oxides (TMOs) is significantly influenced by their surfaces and interfaces, which are pivotal in facilitating charge transfer, ion diffusion, and catalytic reactions. However, intrinsic limitations such as poor conductivity, insufficient active sites, and structural instability often hinder their efficiency. Surface/interface modification addresses these challenges by engineering the material at the atomic and nanoscale levels, thereby enhancing its functional performance. The rational design of transition metal oxide (TMO) surfaces and interfaces is pivotal in advancing electrochemical energy storage and conversion technologies, which involves tailoring the surface electronic structure, optimizing the surface topography, enhancing charge transfer rates, and incorporating vacancy defects. Surface and interface modification offers a plethora of active sites, thereby becoming indispensable in enhancing material properties. This review systematically summarizes the latest advancements in the surface/interface modification of transition metal oxides, with a particular focus on the strategies to enhance the electrochemical performance and stability of these materials in energy storage applications. It begins with a thorough exploration of vacancy engineering and delves into the fundamental mechanisms underlying ion doping. Subsequently, various methods for modifying interfaces and surfaces, including thermal treatment, reduction method, cation/anion doping, plasma treatment, combustion treatment, laser ablation, are meticulously discussed. Furthermore, the crucial role of surface/interface modification of transition metal oxides in catalysis, supercapacitors, and secondary batteries is elaborated in detail. Finally, the review addresses the challenges and future prospects associated with modifying the surfaces/interfaces of transition metals.

Mechanistic insights into the role of N/O-doped biochar in enhanced phenolics production during biomass pyrolysis

Zihang Zhang, Honghui Li, Jinlong Liu, Jusheng Hu, Shurong Wang

2026, 11(3): 724-735. doi: 10.1016/j.gee.2025.07.017

Abstract(292) HTML PDF

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Phenolic compounds are vital chemicals that can be converted into high-density jet fuel components, such as aromatic hydrocarbons or cycloalkanes. Pyrolysis of biomass waste for producing high-value phenolic compounds offers a sustainable approach to waste management and energy conversion. While N/O-doped biochar has demonstrated potential in enhancing phenolics production, its application faces challenges such as complex preparation, high activation temperatures, and unclear catalytic mechanisms. This study addresses these issues by developing a single-step sodium amide (NaNH₂) activation method at mild temperatures (<500 °C) to produce N/O-doped biochar with optimized catalytic properties. Characterization identified graphitic-N (-GN) and oxidized-N (-ON) configurations, along with aldehyde-O (-CHO) and carboxyl-O (-COOH) groups, as key active sites that enhanced catalytic performance. Experimentally, the N/O-doped biochar achieved a phenolics yield of 57.87% at an activation temperature of 400 °C, representing a 19.18% increase over non-catalytic condition. Density functional theory (DFT) calculations further elucidated the role of N and O groups, showing that -GN and -ON in N groups, as well as -CHO and -COOH in O groups, lowered energy barriers in radical-induced demethoxylation, thereby promoting phenolic product formation. Machine learning analysis identified nucleophilicity and local softness as critical descriptors, indicating that these configurations effectively modulated electron density at active sites. These findings provide a comprehensive mechanistic understanding of how specific N and O functional groups in biochar enhance catalytic efficiency in targeted phenolic production.

Enhancing high volumetric energy density of supercapacitors through diatomic reconstruction of layered double hydroxides

Rong Zheng, Lin Sun, Yi Guo, Yu Liu, Qingjun Yang, Wei Zhang, Yulong Ying, Weidong Shi

2026, 11(3): 736-747. doi: 10.1016/j.gee.2025.09.001

Abstract(151) HTML PDF

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Double atom regulation and synergistic phosphorus doping and oxygen vacancy (O_V) engineering are effective strategies for optimizing the electronic structure of layered double hydroxides (LDHs). In this study, a self-supporting P-doped O_V-(Co_0.5Ni_0.5)₃V₂O₈ electrode with interpenetrating carbon nanotube networks was synthesized via cation/anion co-reconstruction. Leveraging vanadium's high valence states, the dual-atom system creates a microporous architecture that enables precise charge redistribution, enhancing both electrical conductivity and OH^- adsorption capacity. Density functional theory confirms that P-O_V synergy reduces charge transfer resistance while optimizing ion diffusion pathways and charge storage kinetics. The optimized electrode achieves outstanding performance: 3807.9 F cm^-3 volumetric capacitance at 1 A g^-1 and exceptional cycling stability (100% capacity retention over 10000 cycles). Assembled asymmetric supercapacitors deliver 158.1 Wh L^-1 energy density at 992 W L^-1 power density, surpassing most reported LDH-based devices. This dual-atom charge redistribution mechanism establishes a universal paradigm for designing high-capacity electrodes, addressing critical challenges in energy storage materials through simultaneous electronic structure modulation and microstructural stabilization.

Clostridium butyricum mineralization of intracellular gold nanoclusters to boost biohydrogen production using visible light

Yaoqiang Wang, Gang Xiao, Jianmin Xing, Haijia Su

2026, 11(3): 748-759. doi: 10.1016/j.gee.2025.12.008

Abstract(100) HTML PDF

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Photocatalytic intracellular biohybrid systems hold great potential for enhancing biohydrogen production using solar energy. However, conventional approaches face nanoparticle toxicity and inefficient transmembrane electron transfer. Here, we developed an intracellular biohybrid system via in-situ biomineralization of gold nanoclusters (Au NCs, 2.15 ± 0.68 nm) within C. butyricum. This biosynthesis leveraged native ion-transport proteins for Au(III) uptake, synthesizing photocatalytically active Au NCs through cysteine-mediated reduction. This intracellular engineering confines photoexcitation and electron transfer within bacterial cells, eliminating transmembrane energy losses. As expected, the photoexcited Au NCs significantly enhanced intracellular NADH regeneration and ATP synthesis compared to dark controls, boosting metabolic reducing power and energy. This resulted in a 70.42% increase in hydrogen production (2.34 mol H₂·mol^-1 glucose). Furthermore, Au NCs eliminated reactive oxygen species (ROS), improving system viability and stability under visible light. This work establishes a platform for engineering biocompatible hybrid systems via endogenous nanophotocatalyst self-assembly.

Peroxymonosulfate activation on the S-scheme heterojunction Bi₄O₅I₂/TiO₂ photoanode of a photocatalytic fuel cell for degradation of tetracyclines with green power generation

Huizhong Wu, Ruiheng Liang, Yujie Chen, Xiuwu Zhang, Jingyang Liu, Zehua Xia, Ignasi Sirés, Minghua Zhou

2026, 11(3): 760-773. doi: 10.1016/j.gee.2025.10.002

Abstract(167) HTML PDF

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Photocatalytic fuel cells (PFC) are green devices for simultaneous contaminant degradation and power generation. However, their performance is still limited due to the inefficient light capture and poor charge transfer at photoanodes. Here, a PFC has been successfully developed using a Bi₄O₅I₂/TiO₂ nanotube arrays (NTAs) S-scheme heterojunction as the photoanode, incorporating peroxymonosulfate (PMS) as synergistic precursor of reactive oxygen species (ROS). A 17-fold increase in rate constant for the degradation of tetracycline (TC) and 6.6-fold increase in maximum power generation was attained in comparison with the TiO₂/light PFC system. A systematic analysis elucidating PMS-mediated regulation of ROS generation and electron transfer was performed. The photocatalytic mechanism, dominated by non-radical ¹O₂ and photogenerated holes (h⁺), led to a maximum photocurrent density (0.091 mA cm^-2) and output power (0.99 mW cm^-2). The current work demonstrates the great robustness of heterojunction-based PFC as new self-powered water decontamination systems.

Carbon nitride-based single-molecular Van der Waals heterojunction for selective photocatalytic CO₂ reduction to CO

Hongjun Dong, Chunhong Qu, Jiaming Li, Deping Wang, Min Zhang, Zuoyi Liu, Liqiu Zhang, Chunmei Li

2026, 11(3): 774-783. doi: 10.1016/j.gee.2025.09.004

Abstract(83) HTML PDF

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Single-molecular heterojunctions have demonstrated significant application potential in the fields of photocatalysis due to prominent photoelectric properties, while the charge transfer behavior still needs to be further discussed. In this work, a fresh single-molecular Van der Waals heterojunction is fabricated through self-assembly of dibromo(1,10-phenanthroline-κN1,κN10)nickel (NiphenBr) molecules on the surface PCN nanosheets, which dramatically boosts the performance of selective photocatalytic CO₂ reduction to CO. This unique assembled architecture effectively regulates electronic band structure and promotes the interfacial transfer and separation of photogenerated carriers owing to the π-π coupling effect between NiphenBr and PCN. Meanwhile, the single-molecular dispersed NiphenBr molecules also prevent their aggregation on PCN under the strong π-π interaction, and further provide abundant single-atom active sites for CO₂ reduction reaction. Therefore, the average rate of photocatalytic reduction of CO₂ to CO for the optimal NiphenBr/PCN-1 sample reaches 5.46 and 2.73 times that of PCN and NiphenBr, respectively. This work opens a new avenue for the single-molecular heterojunction in the application of photocatalytic reactions.

A tunable and universal catalyst for efficient one-pot conversion of xylose to γ-valerolactone

Qiwen Zhan, Ruonan Zhu, Qingchong Xu, Xingjie Wang, Lihong Zhao, Fengxia Yue, Junli Ren

2026, 11(3): 784-791. doi: 10.1016/j.gee.2025.10.012

Abstract(119) HTML PDF

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The one-pot synthesis of γ-valerolactone (GVL) from xylose is crucial for the production of sustainable biofuels and fine chemicals. This study introduces a novel catalyst, Hf-LS-Beta, which is tailored for efficient xylose conversion to GVL, subsequently applied in a tandem process for wheat straw pre-hydrolysate catalysis. The catalyst features dispersed Lewis acid active sites formed through Hf and lignosulfonate sodium (LS) coordination within the Beta porous structure, enhancing accessibility. Both the structure and acidic properties of the catalyst were tunable by varying precursor dosages, with optimal performance achieved at a total Lewis acid content of 118-128 μmol g^-1 and a specific surface area of 171-186 m² g^-1. Under optimized conditions, the Hf (1.5)-LS-Beta (0.4) catalyst delivered the highest GVL yield of 45.71% from xylose and maintained high stability over five cycles. Furthermore, a GVL yield of 29.37% was attained from xylose-rich hydrolysate from wheat straw. This catalyst achieves record-high xylose conversion in isopropanol, efficiently promoting cascade reactions involving dehydration, hydrogenation, ring-opening, and lactonization for GVL formation. Substrate versatility was also demonstrated with the successful conversion of glucose and arabinose, indicating the strong potential for integrated two-step GVL production from lignocellulosic biomass.

Selective hydrogenolysis of lignin to alkene-functionalized monomers over ZnO-modified carbon nanotube supported Pd catalysts

Wen Zhao, Qun Yu, Bingqing Wei, Lei Nie, Fabio Souza Toniolo, Zhenglong Li

2026, 11(3): 792-804. doi: 10.1016/j.gee.2025.10.011

Abstract(158) HTML PDF

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Although current methods enable lignin extraction and depolymerization, the selective hydrogenolysis of lignin into alkene-functionalized monomers remains a significant scientific challenge. These monomers can be further functionalized into diverse natural products or pharmaceutical intermediates, thereby enabling higher-value utilization of biomass resources. Here, we report a catalyst with low Pd loading (0.4 wt%) supported on ZnO-modified carbon nanotubes (Pd/ZnNC) for the selective catalytic hydrogenolysis of the dimer β-O-4 lignin model compound (veratrylglycerol-β-guaiacyl ether, VG) via distinct reaction pathways. The Pd/ZnNC catalyst achieves a selectivity of 37.5% toward alkene-functionalized monomers (1,2-dimethoxy-4-allylbenzene and 1,2-dimethoxy-4-propenylbenzene), approaching 75% of the theoretical maximum selectivity (50%). In contrast, the Pd/CNT catalyst predominantly produces 3-(3,4-dimethoxyphenyl)-1-propanol, and excessive side-chain saturation of monomers is not conducive to subsequent utilization processes. Moreover, the Pd/ZnNC catalyst achieves a conversion rate seven-fold higher than that of commercial catalysts Pd/C (5 wt%). Experimental characterization results demonstrate that the ZnO sites on carbon nanotubes facilitate the dispersion of Pd nanoparticles, resulting in a reduction in particle size. Furthermore, the synergistic effect between ZnO and Pd active sites promotes the selective catalytic formation of monomers containing unsaturated C＝C bonds. The DFT calculations reveal that the Cγ-OH elimination is facilitated by Pd nanoparticles supported on ZnO, which reduces the reaction energy barrier and promotes the generation of propenyl-substituted monomers. The pathway enabled by Pd/ZnNC catalyst offers a great potential for lignin depolymerization into high-value products.

Rigid-flexible dual network hydrogel photoelectrodes for ultrafast and stable catalytic degradation of bisphenol A with minimal metal leaching

Xinmiao Qi, Guoxin Ma, Xiang Xiong, Xin Deng, Ping Jiang, Xin Guo, Yiqiang Wu

2026, 11(3): 805-821. doi: 10.1016/j.gee.2025.11.001

Abstract(147) HTML PDF

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Photoelectrocatalytic (PEC) technologies provide a promising and sustainable approach for the elimination of persistent organic pollutants, but their practical deployment is limited by catalyst deactivation and metal leaching. Here, we proposed a rational design strategy to address this challenge by constructing a rigid-flexible dual network hydrogel photoelectrode (CCMPCu) for ultrafast and stable catalytic degradation of bisphenol A (BPA) with minimal metal leaching. CCMPCu was fabricated by incorporating Cu₂O@ZIF-67 into a chemically cross-linked chitosan/cellulose nanofibril (CNF)-MXene matrix (rigid network), which was further embedded within an in situ polymerized polyaniline network (flexible network). CCMPCu exhibited a high BPA adsorption capacity of 211.1 ± 6.2 mg g^-1, ∼4 × that of Cu₂O@ZIF-67. Under visible light, CCMPCu achieved nearly complete BPA removal (∼100%) within 40 min, with a pseudo-first-order rate constant (k = 0.0836 ± 0.0041 min^-1), representing a ninefold enhancement over Cu₂O@ZIF-67. CCMPCu also showed excellent durability, maintaining over 90% removal efficiency after ten consecutive cycles with negligible Cu (<5 ppb) and Co (<8 ppb) leaching. Mechanistic studies revealed that synergistic integration of the rigid-flexible dual network, MXene, and Cu₂O@ZIF-67 facilitated pollutant preconcentration and photogenerated charge separation, thereby collectively contributing to the enhanced PEC performance. Additionally, CCMPCu showed broad applicability by effectively degrading structurally diverse bisphenol analogues. This work presents a generalizable strategy for fabricating robust, multifunctional CS/CNF-based hydrogel photoelectrodes and offers valuable insights for the sustainable remediation of endocrine-disrupting contaminants.

Heat and hydrogen co-production based on photoresponsive electrode in the full-spectrum SOEC hybrid system

Chen-Ge Chen, Chenyu Xu, Guangyu Deng, Jinhao Mei, Shiyao Wu, Entao Zhang, Yanwei Zhang, Jing-Li Luo

2026, 11(3): 822-841. doi: 10.1016/j.gee.2025.11.002

Abstract(204) HTML PDF

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Facing the growing demand for clean and efficient energy conversion, this study presents the first full-spectrum SOEC hybrid system that co-produces heat and hydrogen by integrating a photoresponsive electrode. The electrode is directly irradiated to generate an additional photocurrent, thereby boosting hydrogen yield, while spectral splitting technology simultaneously supplies the SOEC with both heat and electricity. A comprehensive modeling framework, including the SOEC, balance of plant, and solar photoresponsive models, is developed to evaluate system energy and water flow and to analyze factor interactions within the photoresponsive material. Under optimized conditions, the system achieves an exergy efficiency of 58.98%, a solar-to-hydrogen (STH) efficiency of 28.30%, and a solar-to-thermal (STT) efficiency of 43.78%, offering new theoretical insights and practical design rules for highly efficient, flexible full-spectrum solar hydrogen production.

Engineering oxygen vacancy-rich CoFe₂O₄@C core-shell microreactors via defect-morphology dual synergy for ultrafast peroxymonosulfate activation

Long Sui, Zheng-Tao Dong, Yuan Tian, Lei Ma, Cheng-Gang Niu, Ming Yan, Jia-Jia Wang

2026, 11(3): 842-855. doi: 10.1016/j.gee.2025.11.006

Abstract(149) HTML PDF

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This study innovatively employs a “dual-engineering synergy” strategy combining defect engineering and morphological engineering to construct oxygen vacancy (O_V)-enriched CoFe₂O₄@C core-shell microreactors (O_V-CFO@C) for efficient peroxymonosulfate (PMS) activation. The optimized O_V-CFO@C-500 catalyst exhibits exceptional Fenton-like performance, degrading 97.65% of CIP in 12 min (k_obs = 0.2984 min^-1, 29.25 times that of PMS alone). Structural characterizations confirm successful O_V introduction and core-shell architecture, where carbon cores prevent CoFe₂O₄ agglomeration while enabling reactant enrichment. Theoretical calculations reveal that core-shell structure and O_V modulate d-band center positions and electron delocalization, synergistically enhancing PMS adsorption energy and electron transfer efficiency. Mechanistic studies identify cooperative radical pathways (·OH/SO₄^{·^-} contribution: 54.1%) and non-radical electron transfer processes. Notably, the catalyst demonstrates strong recyclability (88.91% CIP removal after 5 cycles), broad pH tolerance (pH 3-9), low metal ion leaching (<0.06 mg L^-¹), and practical applicability in real water matrices. In continuous-flow degradation systems, 12 h operation achieved sustained removal rates of 96.8% for CIP and 55.2% for total organic carbon (TOC). This study provides new insights into defect-microstructure engineering for advanced oxidation process optimization.

Tailoring a photoreactive biomass-based redox coupled material for interaction enhanced removal of Cr(Ⅵ) and As(Ⅲ)

Yuanyuan Hu, Jun Mao, Yichun Xue, Zhanlong Tan, Fei Xue, Yuqian Yang, Lei Wang, Hongxiang Zhu, Hui He

2026, 11(3): 856-869. doi: 10.1016/j.gee.2025.12.007

Abstract(145) HTML PDF

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Reduction and complete removal of chromium (VI) and arsenic (III) are crucial for the purification of heavy metal-contaminated wastewater. Here, a photo-responsive eucalyptus-based adsorption-catalytic material was engineered by anchoring polyethyleneimine, porous carbon, and iron oxide onto eucalyptus. The material featured a high density of amino and Fe(Ⅱ)/Fe(Ⅲ), the ability to generate free radicals and heat upon light irradiation. High toxicity Cr(Ⅵ) and As(Ⅲ) in water were adsorbed onto the material while catalytically converted into less toxic Cr(Ⅲ) and As(Ⅴ) under light conditions. Notably, the valence cycling of Fe(Ⅱ) and Fe(Ⅲ) during the adsorption process played a critical role in facilitating the redox reactions converting Cr(Ⅵ) to Cr(Ⅲ) and As(Ⅲ) to As(Ⅴ). Furthermore, the preferential Cr(Ⅵ) adsorption on the material generated reactive sites for As(Ⅲ) oxidation, accelerating arsenic adsorption. Consequently, the eucalyptus-based adsorption-conversion material was capable of completely removing 100.0 mg L^-1 of Cr(Ⅵ) and As(Ⅲ), achieving over 95% conversion to the less toxic forms. This work elucidated the synergistic mechanisms underlying the adsorption-conversion processes of Cr(Ⅵ) and As(Ⅲ), providing novel insights into the material design of substances with synergistic and competing functionalities.

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