Abstract: S-doped SnO2 nanoparticles are synthesized by a solid-state process where thermal vaporization of sulfur powder under inert atmosphere to partially sulfurize the SnO2 nanoparticles. In the catalyst, the sulfur concentration is between 0.1 to 2 at%. A catalyst ink can be prepared from the catalyst containing: a liquid carrier; conductive particles; optionally an ionomer, and the catalyst. A gas diffusion electrode comprising the S-SnO2 catalyst dispersed onto a carbon paper electrode is also described.

Abstract: The present disclosure provides hierarchical CuO-derived inverse opal (CuO—IO) electrocatalyst compositions, their synthesis, and their application to selectively convert CO2 into carbon monoxide (CO). The electrocatalyst compositions have a three-dimensional interconnected CuO backbone in hexagonal arrangement. In one embodiment, the compositions have an inverse structure of poly (methyl methacrylate) (PMMA) latex opal. In one embodiment, the electrocatalyst composition inverse-opal structure is comprised of copper-oxide nanoparticles having an average mean diameter ranging from about 15 to about 20 nm. In another embodiment, the compositions have an average cavity size of 175 to 185 nm.

Abstract: Three-dimensional (3D) hollow nanosphere electrocatalysts that convert CO2 into formate with high current density and Faradaic efficiency (FE). The SnO2 nanospheres were constructed from small, interconnected SnO2 nanocrystals. The size of the constituent SnO2 nanocrystals was controlled between 2-10 nm by varying the calcination temperature and observed a clear correlation between nanocrystal size and formate production. In situ Raman and time-dependent X-ray diffraction measurements confirmed that SnO2 nanocrystals were reduced to metallic Sn and resisted microparticle agglomeration during CO2 reduction. The nanosphere catalysts outperformed comparably sized, non-structured SnO2 nanoparticles and commercially-available SnO2 with a heterogeneous size distribution.