Enhanced photocatalytic splitting of photothermally induced water vapor to evolve hydrogen

Solar energy conversion using photocatalytic water splitting shows promising potential for resolving the current energy crisis. To split vapor into hydrogen in this study, we built a surface carbonized wood/TiO2 (C-wood/TiO2) photothermal-photocatalytic system. Natural wood that had been surface carbonized enabled stable steam production and produced a solid/gas reaction interface with a lower Gibbs free energy, enabling TiO2 to produce hydrogen photocatalytically without the need for a co-catalyst made of a noble metal. The carbonized surface was able to transfer photogenerated electrons quickly from TiO2, while also significantly enhancing solar spectrum absorption. The C-wood/TiO2 system demonstrated efficient solar spectrum utilization in vapor production and hydrogen evolution. The C-wood/TiO2 system's hydrogen evolution rate under AM 1.5G light irradiation was 487.4 μmol·m−2·h−1 when using deionized water, and the cycling experiment demonstrated long-term stability. Additionally, this system could evolve hydrogen from seawater (248.1 μmol·m−2·h−1). This study showed the photothermal-photocatalytic biphasic system's strong suit and potential for producing hydrogen.