Insights and Progress on Photocatalytic and Photoelectrocatalytic Reactor Configurations and Materials for CO₂ Reduction to Solar Fuels

Abstract

Excessive greenhouse gas (GHG) emissions arising from nonrenewable fossil fuel utilization are causing serious climate change. Since carbon dioxide (CO 2 ) contributes about 76% of GHGs in the atmosphere, utilization of CO 2 could reduce its negative impact on the environment. Among the technologies available for CO 2 conversion, photocatalytic (PC) and photoelectrocatalytic (PEC) reduction of CO 2 into valuable solar fuels have made significant progress. These two technologies are environmentally friendly and effective in concurrently solving energy crises. Insights on the principles, thermodynamics, and limitations of photocatalysis/photoelectrocatalysis using sustainable energy for reducing CO 2 are elucidated in this review. The configurations of cathode−anode and the proton exchange membrane in PEC membrane reactors are discussed. The advances of photoelectrocatalysts such as titania, copper oxides, complex metal−organic frameworks (MOFs), membrane-based immobilized, and metallic photoelectrocatalysts for PEC reduction of CO 2 are also incorporated. Discussion of possible reaction mechanisms using DFT simulation to postulate feasible pathways occurring on catalyst surfaces is presented. It is recognized that PEC CO 2 reduction is critical in the utilization of CO 2 and solar energy research. It is also deduced that advances in reactor configurations along with photoelectrocatalyst materials are vital in mitigating excess CO 2 emissions to generate solar fuels.

Review on CO2 Management: From CO2 Sources, Capture, and Conversion to Future Perspectives of Gas-Phase Electrochemical Conversion and Utilization

“…This route involves thermal and plasma procedures. The second route is direct CO 2 conversion, in which the required hydronium ion is produced in the integrated electrochemical, photochemical, or photoelectrochemical reactor . Accordingly, five foremost CO 2 conversion techniques have been developed, which are schematically presented in Figure : thermal, plasma, photochemical, biochemical, and (photo)­electrochemical methodologies.…”

Coal-Fired Power Plants Using Ammonia for Flexibility Enhancement under Carbon Control Strategies: Status, Development, and Perspectives

“…Carbon dioxide, a primary component of greenhouse gases, constitutes approximately 76% of the total greenhouse gas volume in the atmosphere. Numerous scientific studies have established a direct link between carbon dioxide emissions and global climate change. , In response to the pressing need to mitigate global warming, an increasing number of countries are committing to reducing carbon emissions. Governments worldwide have started to rigorously monitor and regulate carbon dioxide emissions.…”

Sulfidation-Induced Surface Local Electronic and Atomic Structures in a Silver Catalyst Enables Silicon Photocathode for Selective and Efficient Photoelectrochemical CO2 Reduction

“…The photoelectrochemical (PEC) CO 2 reduction reaction (CO 2 RR), which directly converts greenhouse gases into carbon-based fuels using inexhaustible solar energy, is a tempting route for mitigating the current energy crisis and environmental degradation. − The semiconductor photoelectrode is the key component for a PEC device. − Silicon (Si) has the advantages of low cost, narrow band gap (1.12 eV), high carrier mobility, and favorable energy band structure for various reduction reactions, demonstrating enormous application prospects in PEC photocathodes. , However, naked Si photocathode often comes up against low selectivity and slow kinetics toward CO 2 RR owing to the diverse possible reaction pathways and the competitive hydrogen evolution reaction (HER). − These bottlenecks have inspired numerous researchers to rationally design an appropriate catalyst and integrate it with Si photocathode effectively, aiming for achieving single-carbon products with high efficiency. , …”