Low‐Coordination Single Au Atoms on Ultrathin ZnIn₂S₄Nanosheets for Selective Photocatalytic CO₂Reduction towards CH₄

Abstract

Selective CO 2 photoreduction to hydrocarbon fuels such as CH 4 is promising and sustainable for carbonneutral future. However, lack of proper binding strengths with reaction intermediates makes it still a challenge for photocatalytic CO 2 methanation with both high activity and selectivity. Here, low-coordination single Au atoms (Au 1 -S 2 ) on ultrathin ZnIn 2 S 4 nanosheets was synthesized by a complex-exchange route, enabling exceptional photocatalytic CO 2 reduction performance. Under visible light irradiation, Au 1 /ZnIn 2 S 4 catalyst exhibits a CH 4 yield of 275 μmol g À 1 h À 1 with a selectivity as high as 77 %. As revealed by detailed characterizations and density functional theory calculations, Au 1 / ZnIn 2 S 4 with Au 1 -S 2 structure not only display fast carrier transfer to underpin its superior activity, but also greatly reduce the energy barrier for protonation of *CO and stabilize the *CH 3 intermediate, thereby leading to the selective CH 4 generation from CO 2 photoreduction.

Rich Sulfur Vacancies and Reduced Schottky Barrier Height Synergistically Enable Au/ZnIn2S4 with Enhanced Photocatalytic CO2 Reduction into CO

“…For V S R-ZIS MFs, the high-resolved Zn 2p spectrum (Figure b) can be decomposed into two peaks at 1045.4 and 1022.3 eV, which are identified as Zn 2p 1/2 and Zn 2p 3/2 states of Zn 2+ , respectively. , In Figure c, the doublets placed at 452.7 and 445.1 eV result from In 3d 3/2 and In 3d 5/2 states of In 3+ , respectively. , In addition, as displayed in Figure d, we can deconvoluted the S 2s XPS spectrum of V S R-ZIS MFs into two peaks centered at 162.9 and 161.7 eV, being contributed to S 2p 1/2 and S 2p 3/2 of S 2– . , Figure e manifests that the binding energies of 88.9 and 84.8 eV derive from Au 4f 5/2 and Au 4f 7/2 , respectively, coinciding with the reference values for Au 0 , and proving the presence of Au NPs in Au/ZIS-0.4 . Noteworthily, the binding energies of Zn 2p, In 3d, and S 2s in V S R-ZIS MFs negatively shift by 0.1 eV, compared with those of V S P-ZIS MFs, (Figure b–d), evincing the existence of rich S vacancies in the V S R-ZIS MFs owing to the escape of more S atoms . Meanwhile, the three relevant peaks in Au/V S R-ZIS-0.4 positively shift by 0.2 eV with respect to those in V S R-ZIS MFs (Figure b–d), confirming that the electrons in V S R-ZIS MFs spontaneously transfer into Au NPs because electronic interactions exist at the interface after the close contact of V S R-ZIS MFs and Au NPs .…”

High-performance artificial leaf: from electrocatalyst design to solar-to-chemical conversion

“…29,30 In order to mitigate the increasing greenhouse effect and achieve the global zerocarbon goal, the development of efficient ways to reduce CO 2 to high value-added chemicals is important for both scientific research and practical applications. [31][32][33][34][35] As multiple proton-coupled electron transfer (PCET) processes are involved in the CO 2 RR, a wide range of products can be generated, 36 including carbon monoxide (CO), formic acid (HCOOH), methanol (CH 3 OH), ethylene (C 2 H 4 ), ethanol (CH 3 CH 2 OH), n-propanol (CH 3 CH 2 CH 2 OH) and many others (Fig. 3).…”

Comprehensive Insight into Construction of Active Sites toward Steering Photocatalytic CO2 Conversion

“…Furthermore, single Au atoms are prone to formation of stronger bonds with *CO intermediates, greatly reduced the energy barrier for protonation of *CO, and stabilized the *CH 3 intermediate, which allowed selective CH 4 generation from CO 2 photoreduction. [24] Notably, the generation of CH 3 OH competes with CH 4 , as their formation pathways contain common intermediates. Specifically, *CO can be converted to CH 3 OH, without a dehydration process, by constantly adding electrons and hydrogenation (*CO + H + + e − → *CHO + H + + e − → *CH 2 O + H + + e − → *CH 3 O+ H + + e − → *CH 3 OH).…”