Hydrophobic-treated yolk-shell SnS₂@CSs Z-scheme confinement reactor for solar-electro-driven hydrogen peroxide...

The diffusion and adsorption properties of the O₂/H₂O corpuscles at active sites play a crucial role in the fast photo-electrocatalytic reaction of hydrogen peroxide (H₂O₂) production. Herein, SnS₂ nanosheets with abundant interfacial boundaries and large specific areas are encapsulated into hollow mesoporous carbon spheres (CSs) with flexibility, producing a yolk-shell SnS₂@CSs Z-scheme photocatalyst. The nanoconfined microenvironment of SnS₂@CSs could enrich O₂/H₂O in catalyst cavities, which allows sufficient internal O₂ transfer, improving the surface chemistry of catalytic O₂ to O₂^- conversion and increasing reaction kinetics. By shaping the mixture of SnS₂@CSs and polytetrafluoroethylene (PTFE) on carbon felt (CF) using the vacuum filtration method, the natural air-breathing gas diffusion photoelectrode (AGPE) was prepared, and it can achieve an accumulated concentration of H₂O₂ about 12 mM after a 10 h stability test from pure water at natural pH without using electrolyte and sacrificial agents. The H₂O₂ product is upgraded through one downstream route of conversion of H₂O₂ to sodium perborate. The improved H₂O₂ production performance could be ascribed to the combination of the confinement effect of SnS₂@CSs and the rich triple phase interfaces with the continuous hydrophobic layer and hydrophilic layer to synergistically modulate the photoelectron catalytic microenvironment, which enhanced the transfer of O₂ mass and offered a stronger affinity to oxygen bubbles. The strategy of combining the confined material with the air-breathing gas diffusion electrode equips a wide practical range of applications for the synthesis of high-yield hydrogen peroxide.