Photoelectrocatalytic Reduction of CO₂ for Efficient Methanol Production: Au Nanoparticles as Electrocatalysts and Light Supports

Abstract

Conversion of CO2 into value-added fuels and chemicals faces the challenges of high overpotential, low selectivity for desired products, and sluggish multi-electron transfer kinetics. Plasmon-mediated electrocatalytic methods show potential for overcoming these problems. In this work, choosing Au nanoparticles (NPs) as the dual-functional material of the electrocatalyst and plasmonic support, methanol can be efficiently produced from CO2 reduction. The dependences of current density and Faradaic efficiency (FE) on the Au NP size, light wavelength, and light density are systematically investigated. The performance test results show that CH3OH with FE as high as 52% can be obtained at a potential of −0.8 V (vs RHE) when a 20.2 nm Au NP-modified glass carbon electrode is under excitation using 520 nm light with a light density of 120 mW/cm2. The performance results, along with the discrete dipole approximation calculation and electrochemical characterizations, suggest that the efficient activation of CO2 by plasmon-generated energetic electrons accounts for the enhanced conversion rate and the high selectivity for CH3OH production.

Rational‐Designed Principles for Electrochemical and Photoelectrochemical Upgrading of CO2 to Value‐Added Chemicals

“…For example, Wang's group reported an Ag nanoparticle decorated p-Si nanowire array catalyst, [133] which could realize photoelectrocatalytic CO 2 reduction to syngas with the adjustable H 2 /CO molar ratio ranging from 1 to 4. The Ag nanoparticles with the size of 8.2 nm provide a balance between *CO formation and CO adsorption, which selectively produced CO prod- [135] Copyright 2020, American Chemical Society. c) EtOH yields of CuFeO 2 /Nb-TNTs photocathode with different coating amounts at −0.4 V under illumination.…”

“…Plasmon‐mediated electrocatalysis has been regarded as a promising approach to realize highly active and selective CO 2 conversion into higher value‐added chemicals. For example, Lu et al found that the plasmonic Au was an ideal catalyst to generate abundant electrons with high photon energy, [ 135 ] which could be easily injected into CO 2 molecules and intermediates to activate the overall reaction system. Meanwhile, the generated photon flux would initiate C—C coupling toward high‐order product formation ( Figure 17 a ).…”

“…b) Schematic illustration of the proposed mechanism of SPR-mediated CO 2 RR in photoelectrolysis by using Au NPs-modified GC cathode. Reproduced with permission [135]. Copyright 2020, American Chemical Society.…”

A Critical Review on Black Phosphorus‐Based Photocatalytic CO2 Reduction Application

“…[95][96][97] In detail, the generated electrons of the conduction bands can take part in the CO 2 reduction reaction, while the generated holes of the valence band usually get involved in some water oxidation. [98,99] Furthermore, the photocatalytic reduction of CO 2 has many kinds of catalytic products including CO, CH 3 OH, HCOOH, CH 4 , etc. due to its reaction may involve the catalytic process of 2-8 electrons (Equations ( 1)-( 7)).…”

Efficient Electrochemical Reduction of CO2 to CO in Ionic Liquid/Propylene Carbonate Electrolyte on Ag Electrode

“…The catalytic transformation of CO 2 into value-added chemicals and fuels has been regarded as one of the most promising ways to realize the valorization of CO 2 [5]. In this context, several strategic options, including electrochemical [6][7][8][9][10][11][12], thermochemical [13][14][15], photocatalytic [16][17][18] and photoelectrochemical [19][20][21][22] approaches, have been developed to undertake the CO 2 conversion. Among them, the electrochemical reduction of CO 2 is regarded as the most prospective way, because it allows one to combine with carbon capture and storage technology, and to utilize renewable energy (such as solar energy and wind energy), as inputting energy and water as a reductant to reduce CO 2 into various carbon-based fuels and chemicals (e.g., CO, HCOOH, CH 4 , C 2 H 4, and CH 3 OH) in a modular electrochemical reactor under ambient temperature and pressure [7][8][9][10][11].…”