Photocatalytic Water Splitting of Al-Doped Rh x Cr2-x O3/SrTiO3 Synthesized by Flux Method: Elucidating the Role of Different Molten Salts

Photocatalytic water splitting isa promising approachto convertingsolar energy into green hydrogen. As an effective photocatalyst, Rh (x) Cr2-x O3/SrTiO3 has been widely studied for water splitting,mainly synthesized using SrCl2 molten salt as the reactionmedia. This research systematically studied the effect of molten saltsand Al doping in order to test and integrate the combinatorial effectof the modifications of SrTiO3-based catalysts. A seriesof SrTiO3 and Al-doped SrTiO3 (Al:SrTiO3) were synthesized by the flux method with three molten salts(NaCl, KCl, and SrCl2 center dot 6H(2)O) at differentannealing temperatures (900 and 1000 degrees C). Cocatalyst, Rh (x) Cr2-x O3, was loaded on the surface of Al-doped SrTiO3 byimpregnation and photodeposition methods for comparison. The photocatalyticperformance of overall water splitting was evaluated in pure waterunder UV and AM 1.5G simulated sunlight. A significant improvementin photocatalytic activity was observed in Al-doped Rh (x) Cr2-x O3/SrTiO3. Especially Al-doped Rh (x) Cr2-x O3/SrTiO3 synthesized by KCl molten salt showed the highest hydrogen evolutionrate with the synergy effect of molten salt and Al doping. Furthermore,hydrogen evolution rates were further enhanced by loading core-shellRh (x) Cr2-x O3 using in situ photodeposition instead of impregnation,reaching 784 and 431 mu mol h(-1) g(-1) H-2 under 365 nm UV light and AM 1.5G irradiation, respectively.

Automated summary

Photocatalytic water splitting is a promising approach for converting solar energy into green hydrogen. This study investigated the combinatorial effect of molten salts and Al doping on the performance of SrTiO3-based catalysts for water splitting. The results showed that Al-doped Rh (x) Cr2-x O3/SrTiO3 synthesized using KCl molten salt exhibited the highest hydrogen evolution rate and photocatalytic activity. Moreover, loading core-shell Rh (x) Cr2-x O3 using in situ photodeposition further enhanced the hydrogen evolution rates under different light sources.