Insights into Electrochemical CO₂ Reduction on SnS₂: Main Product Switch from Hydrogen to Formate by Pulsed Potential Electrolysis

Abstract

Tin disulfide (SnS 2 ) is a promising candidate for electrosynthesis of CO 2 -to-formate while the low activity and selectivity remain a great challenge. Herein, we report the potentiostatic and pulsed potential CO 2 RR performance of SnS 2 nanosheets (NSs) with tunable S-vacancy and exposure of Sn-atoms or S-atoms prepared controllably by calcination of SnS 2 at different temperatures under the H 2 /Ar atmosphere. The catalytic activity of S-vacancy SnS 2 (V s -SnS 2 ) is improved 1.8 times, but it exhibits an exclusive hydrogen evolution with about 100 % FE under all potentials investigated in the static conditions. The theoretical calculations reveal that the adsorption of *H on the V s -SnS 2 surface is energetically more favorable than the carbonaceous intermediates, resulting in active site coverage that hinders the carbon intermediates from being adsorbed. Fortunately, the main product can be switched from hydrogen to formate by applying pulsed potential electrolysis benefiting from in situ formed partially oxidized SnS 2À x with the oxide phase selective to formate and the S-vacancy to hydrogen. This work highlights not only the V s -SnS 2 NSs lead to exclusively H 2 formation, but also provides insights into the systematic design of highly selective CO 2 reduction catalysts reconstructed by pulsed potential electrolysis.

Enhanced photocatalytic performance of SnS2 under visible light irradiation: strategies and future perspectives

“…Presently, the total number of publications on SnS 2 as a photocatalyst remains at less than 500, significantly lower compared with conventional photocatalysts such as TiO 2 or ZnO, and even other transition metal dichalcogenide (TMD) materials like MoS 2 and WS 2 (based on Scopus data). As a 2D photocatalyst material, SnS 2 has found applications across various domains, including air purification, 44,55 wastewater treatment, 47,84–87 hydrogen production, 88–97 and antibacterial purposes, 41 CO 2 reduction, and 89,91,98–100 nitrogen fixation. 92,94,101…”

Progress and Perspectives of Pulse Electrolysis for Stable Electrochemical Carbon Dioxide Reduction

“…Recently, Huang et al 127 also demonstrated that the selectivity switch from H 2 to HCOO − during CO 2 electroreduction on SnS 2 -based electrodes can be achieved through pulse potential electrolysis. First, they synthesized SnS 2 nanosheets (NS) on carbon by a solvothermal reaction then the SnS 2 NS precursor was engineered to sulfur-vacancy SnS 2 (V s -SnS 2 ), calcinated at 400 °C for 30 min under a H 2 /Ar atmosphere, with a well-preserved morphology.…”

“…(c) ECR performance on SnS 2 and (d) V s -SnS 2 after applying the pulse electrolysis strategy. Reprinted with permission from ref . Copyright 2023 John Wiley and Sons.…”

Copper Electrocatalyst Produced by Cu2(OH)2CO3-Mediated In Situ Deposition for Diluted CO2 Reduction to Multicarbon Products

“…Although studies on electroreduction of diluted CO 2 to multicarbon products is relatively limited, recent studies of pure CO 2 reduction to C 2 provide an important reference. Among various metals such as gold, silver, tin, and so forth, copper as well as its alloys and compounds is widely studied due to its unique property to facilitate C–C coupling. − Besides, the electrocatalytic CO 2 reduction performances can be tuned by adjusting the interaction between reaction intermediates and the Cu surface. , Previous studies on CO 2 reduction showed that the adsorbed hydroxyl groups (OH*) formed on the Cu surface could affect the adsorption energy of CO and the reaction rate of C–C coupling . Further, a high coverage of CO on the catalyst surface can help facilitate CO 2 reduction against HER, especially under diluted CO 2 conditions …”

“…8−12 Although studies on electroreduction of diluted CO 2 to multicarbon products is relatively limited, recent studies of pure CO 2 reduction to C 2 provide an important reference. Among various metals such as gold, 13 silver, 14 tin, 15 and so forth, copper as well as its alloys and compounds is widely studied due to its unique property to facilitate C−C coupling. 16−18 Besides, the electrocatalytic CO 2 reduction performances can be tuned by adjusting the interaction between reaction intermediates and the Cu surface.…”