Stabilizing indium sulfide for CO2 electroreduction to formate at high rate by zinc incorporation

Recently developed solid-state catalysts can mediate carbon dioxide (CO2) electroreduction to valuable products at high rates and selectivities. However, under commercially relevant current densities of > 200 milliamperes per square centimeter (mA cm−2), catalysts often undergo particle agglomeration, active-phase change, and/or element dissolution, making the long-term operational stability a considerable challenge. Here we report an indium sulfide catalyst that is stabilized by adding zinc in the structure and shows dramatically improved stability. The obtained ZnIn2S4 catalyst can reduce CO2 to formate with 99.3% Faradaic efficiency at 300 mA cm−2 over 60 h of continuous operation without decay. By contrast, similarly synthesized indium sulfide without zinc participation deteriorates quickly under the same conditions. Combining experimental and theoretical studies, we unveil that the introduction of zinc largely enhances the covalency of In-S bonds, which “locks” sulfur—a catalytic site that can activate H2O to react with CO2, yielding HCOO* intermediates—from being dissolved during high-rate electrolysis.

A Modeling Study on Utilizing In2S3 as the Buffer Layer of Cu(In,Ga)Se2 Based Solar Cell

In Cu(In1 − x,Gax)Se (CIGS)-based solar cells, the cadmium sulfide (CdS) layer is conventionally used as a buffer layer. In the current study, the CdS layer was replaced by the Indium sulfide (In2S3) layer, and the impact of various concentrations of Ga in the CIGS absorber, the band gap of the In2S3 buffer layer, and the band gap of the NayCu1−yIn5S8 interfacial layer on the efficiency of these CIGS solar cells were investigated. The results indicated that in the absence of NayCu1−yIn5S8, the optimal performance was obtained with an Eg−In2S3 value of 3.1 eV and the ratio of Ga/(Ga + In) (GGI) = 1, yielding an efficiency of 21.97%. The formation of the NayCu1−yIn5S8 interfacial layer deteriorated the efficiency of the device, and the highest efficiency of the CIGS solar cells with the interfacial layer was 16.33 %.