Manipulating Intermediates at the Au–TiO₂ Interface over InP Nanopillar Array for Photoelectrochemical CO₂ Reduction

Abstract

Photoelectrochemical (PEC) reduction of CO 2 with H 2 O is a promising approach to convert solar energy and greenhouse gas into valueadded chemicals or fuels. However, the exact role of structures and interfaces of photoelectrodes in governing the photoelectrocatalytic processes in terms of both activity and selectivity remains elusive. Herein, by systematically investigating the InP photocathodes with Au−TiO 2 interfaces, we discover that nanostructuring of InP can not only enhance the photoresponse owing to increased light absorption and prolonged minority carrier lifetime, but also improve selectivity toward CO production by providing more abundant interfacial contact points between Au and TiO 2 than planar photocathodes. In addition, theoretical studies on the Au−TiO 2 interface demonstrate that the charge transfer between Au and TiO 2 , which is locally confined to the interface, strengthens the binding of the CO* intermediate on positively charged Au interfacial sites, thus improving CO 2 photoelectroreduction to form CO. An optimal Au−TiO 2 /InP nanopillar-array photocathode exhibits an onset potential of +0.3 V vs reversible hydrogen electrode (RHE) and a Faradaic efficiency of 84.2% for CO production at −0.11 V vs RHE under simulated AM 1.5G illumination at 1 sun. The present findings of the synergistic effects of the structure and interface on the photoresponse and selectivity of a photoelectrode provide insights into the development of III−V semiconductor-based PEC systems for solar fuel generation.

Solar-Driven Carbon Dioxide Reduction: A Fair Evaluation of Photovoltaic-Biased Photoelectrocatalysis and Photovoltaic-Powered Electrocatalysis

“…The efficiency of this solar cell is as high as 16.7%, which is twice the efficiency of the previous semi-transparent solar cell. So far, it is noteworthy that the proposed PV-PEC CO 2 RR device (Figure 1B) is totally different from diverse devices reported in literature (Abdi et al, 2013;Jang et al, 2015;Jang et al, 2016;Rothschild and Dotan, 2017;Song et al, 2017;Young et al, 2017;Hu et al, 2018;Gurudayal et al, 2019;Li et al, 2019;Kan et al, 2020;Kempler et al, 2020;Zhang et al, 2020;Liu et al, 2021a;Dong et al, 2021).…”

Ultrasonic-assisted oxidation of cellulose to oxalic acid over gold nanoparticles supported on iron-oxide

“…To our knowledge, this is the first example of the charge transfer from Au to Fe 2 O 3 , previous reports being focussed on TiB 2 or TiO 2 supports. 50,51 One should note that the charge transfer between Au and Fe 2 O 3 occurred with a much higher magnitude than with previously reported supports, highlighting the strong ability of Fe 2 O 3 in modifying the electronic properties, and thus the catalytic activity, of supported Au atoms. Further demonstrating that the interface Au-Fe 2 O 3 is more likely to play a major role in the cellulose depolymerisation oxidation reaction mechanism.…”

Powering the World with Solar Fuels from Photoelectrochemical CO2 Reduction: Basic Principles and Recent Advances

“…Ever since the first report by Halmann [13] in 1978, where he realized the CO 2 reduction on a p-type GaP photocathode in the presence of light irradiation and water, various semiconductors have been explored to carry out the PEC CRR, including InP, [14,15] ZnTe, [16,17] a/p-Si, [18][19][20] Cu 2 O, [21][22][23] and encapsulated photovoltaic perovskites, [24] etc. Also, other types of PEC CRR cells that combine a photoanode (such as TiO 2 , BiVO 4 , n-Si) and a CRR dark-or photo-cathode are developed to broaden the PEC CRR systems.…”

“…Despite the metal cocatalysts, the construction of a metal-oxide interface to modulate the adsorption of intermediates is also found to be another kind of cocatalyst for PEC CO production. [14,53] In addition, the typical CO-production single-atom catalysts (SAC) [54] and molecular catalysts [55][56][57] are also reported to be attached to semiconductors for PEC CO production. As for the semiconducting substrates, various materials including p-Si, [18,19] InP, [14,15] ZnTe, [16,17] CuBi 2 O 4 , [58] Cu 2 ZnSnS 4 , [59,60] and perovskites [24] have been utilized and assembled with/without cocatalyst to fabricate the CO 2 -reduction photocathodes.…”

“…[14,53] In addition, the typical CO-production single-atom catalysts (SAC) [54] and molecular catalysts [55][56][57] are also reported to be attached to semiconductors for PEC CO production. As for the semiconducting substrates, various materials including p-Si, [18,19] InP, [14,15] ZnTe, [16,17] CuBi 2 O 4 , [58] Cu 2 ZnSnS 4 , [59,60] and perovskites [24] have been utilized and assembled with/without cocatalyst to fabricate the CO 2 -reduction photocathodes. At present, the PEC CO 2 reduction cell with a 100% FE for CO production has been achieved.…”