The conversion of solar energy to facilitate the photocatalytic transformation of CO2 into CH4 addresses the energy shortage caused by reducing humans’ excessive dependence on fossil fuels and contributes substantially to the goal of carbon neutrality. However, there are still many limitations on the conversion of CO2 to CH4. In this work, a series of ZrO2/Bi19S27Br3 composite photocatalysts was prepared by the solvothermal method and applied to the methanation reaction of CO2. Combining Bi19S27Br3 with ZrO2 forms a heterojunction with a strong coupling interface. This greatly enhanced the CO2 adsorption performance of the 50-ZrO2/Bi19S27Br3 composite and promoted the effective separation of photogenerated electron–hole pairs. Without the addition of photosensitizers, the CH4 selectivity of the 50-ZrO2/Bi19S27Br3 composite is approximately 63%, and the CH4 generation rate is 18.04 μmol/(gcat·h), which is noticeably higher than that of ZrO2 or Bi19S27Br3. This research demonstrated enhanced photocatalytic CO2 reduction efficiency using Bi19S27Br3-based materials, providing a novel approach for the use of CO2 resources.
The efficient recovery of silver (Ag) from retired photovoltaic (PV) panels is crucial for resource sustainability and environmental protection. This study developed an environmentally friendly leaching method using ammonia (NH3·H2O) and hydrogen peroxide (H2O2), achieving the selective dissolution of Ag from retired crystalline silicon solar panels. Meanwhile, nonprecious metals such as aluminum (Al) and lead (Pb), which are commonly found in PV cells, were barely dissolved, demonstrating the excellent selectivity of this method for Ag. Light irradiation significantly improved the dissolution efficiency of Ag and reduced the amount of the reagent used. Ag dissolution occurred owing to a dual-pathway synergistic effect, which stemmed from the direct oxidation of Ag by H2O2. The strongly oxidizing hydroxyl radicals generated by photocatalysis accelerated the oxidation and dissolution of Ag. In addition, NH3·H2O effectively promoted the dissolution and stabilization of oxidation products by forming soluble Ag–NH3·H2O complexes ([Ag(NH3)2]+). This article reports an efficient, selective, and environmentally friendly strategy of Ag recovery and elucidates the radical-mediated dissolution mechanism under light-driven conditions, offering a feasible way for sustainably recovering valuable metals from retired PV panels.
Stack-integrated methanol steam reformer (MSR)/high-temperature proton exchange membrane fuel cell (HT-PEMFC) systems enable simultaneous hydrogen production and power generation within monolithic devices, significantly reducing system complexity and costs. However, in situ heat exchange between endothermic reforming layers and exothermic fuel cell layers creates complex thermal interactions under variable loads, posing a critical challenge to stable operation. Here, we systematically evaluate the adiabatic operational limits of a fully coupled stack-integrated MSR/HT-PEMFC using three-dimensional computational fluid dynamics. Although thermoneutral operation can be achieved at 0.4 A/cm2 under isothermal conditions, adiabatic operation introduces temperature gradients exceeding 30 °C and elevates reformate carbon monoxide (CO) concentrations beyond 2000 × 10−6, which can irreversibly degrade fuel cell performance. Parametric analysis reveals a critical trade-off: reducing voltage or increasing methanol feed rates lowers CO levels by 38% but degrades system efficiency by 15%, highlighting an inherent safety–efficiency conflict in adiabatic systems. These findings underscore the necessity of coordinated voltage and methanol feed flow regulation, as well as strategic decoupling of MSR and PEMFC for practical implementation.
Electrocatalytic C–N coupling technology offers a promising route for green and sustainable urea synthesis. However, this route faces challenges of low urea yield and Faradaic efficiency due to the high dissociation energy of atomic bonds in reactants, complex reaction intermediates, high reaction energy barriers, and competing side reactions. As C–N coupling involves the synergistic action of two or more active sites, it is crucial to develop efficient multi-active-site catalysts to address these challenges. This review analyzes the reaction mechanisms of electrocatalytic C–N coupling for urea synthesis and summarizes effective strategies to achieve multi-active-site catalysts, including heteroatom doping, defect engineering, heterojunctions, and diatomic catalysts. Furthermore, based on this analysis, we propose the universal design principles for high-efficiency multi-activesite catalysts.
The increasing demand for sustainable energy storage solutions has intensified the focus on high-performance supercapacitors, known for their rapid charge/discharge capabilities, high power density, and long cycle life. Polyurethane (PU)-based materials have gained attention as promising candidates for supercapacitor electrodes, due to their flexibility, mechanical robustness, and tunable properties. It is important to clarify that PU typically does not contribute directly to charge storage via adsorption or pseudocapacitive mechanisms. Instead, PU serves as a flexible scaffold, a binder, or a precursor for the preparation of heteroatom-doped carbon materials upon thermal treatment. Thus, the term 'PU-based' in this review refers to PU-supported or PU-derived composites, where PU enables structural or functional integration of active electrode Materials. Polyurethane composites incorporating graphene oxide have demonstrated a specific capacitance of 758.8 mF/cm2 with capacitance retention of 92% over 5,000 cycles. Other PU-based electrodes have achieved energy densities up to 22.5 Wh/kg and power densities of 1472.7 W/kg, reflecting their potential for high-performance energy storage applications. Despite these advantages, challenges, such as low intrinsic conductivity and the environmental impact of traditional synthesis methods, limit their widespread adoption. Conventional PU composites often incorporate conductive additives like carbon materials, metal oxides, or conductive polymers to enhance their electrochemical performance, yet these approaches may involve non-renewable or toxic components. Developing green energy materials that adhere to sustainability and green chemistry principles is crucial to address these limitations. This includes using renewable resources, environmentally friendly processing techniques, and recyclable materials to reduce the ecological footprint and meet the growing need for sustainable energy storage technologies. This review highlights current trends in developing eco-friendly supercapacitor materials, addressing key challenges such as limited conductivity and complex processing. It uniquely integrates green chemistry principles with advances in polyurethane composites, emphasizing sustainable feedstocks, heteroatom doping, and functional nanomaterials. By combining these aspects, this review provides a comprehensive perspective not fully covered in existing literature.
Global water scarcity, intensified by climate change and population growth, necessitates sustainable freshwater solutions. Solar thermal desalination offers promise due to its energy efficiency, yet optimizing system performance hinges critically on material selection, particularly for photothermal absorbers and their substrates. While extensive research addresses photothermal nanomaterials, substrate materials vital for structural integrity, thermal management, and interfacial stability remain underexplored. This review comprehensively examines current advances in solar evaporator components, evaluating photothermal materials and substrates against key selection criteria: thermal conductivity, stability under harsh conditions, scalability, and compatibility. We analyze diverse substrate materials (e.g., metals, ceramics, polymers, bio-based, and aerogels) and their synergistic roles in enhancing evaporation efficiency and durability. Critical gaps in large-scale feasibility, long-term stability under variable solar flux, and cost-performance trade-offs are identified. The review also highlights emerging trends such as 3D-printed substrates and bio-inspired designs to overcome salt accumulation and fouling. By addressing these challenges and outlining pathways for scalable implementation, this work aims to advance robust, economically viable solar thermal desalination technologies for global freshwater security.