Modification of ZnS1−x−0.5yOx(OH)y–ZnO photocatalyst with NiS for enhanced visible-light-driven hydrogen generation from seawater

• Published in: International journal of hydrogen energy 2013-12, Vol.38 (36), p.15976-15984
• Main Authors: Li, Yuexiang, Lin, Shiyi, Peng, Shaoqin, Lu, Gongxuan, Li, Shuben
• Format: Article
• Language: English
• Subjects: Alternative fuels. Production and utilization; Applied sciences; Energy; Exact sciences and technology; Fuels; Hydrogen; Hydrogen production; Modification method; NiS; Photocatalysis; Seawater
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2013.09.149

NiS was loaded on ZnS1−x−0.5yOx(OH)y–ZnO photocatalyst by two methods (depositing NiS on the photocatalyst via impregnation with a NiS sol and via a precipitation reaction). The activity of the NiS-modified photocatalyst for hydrogen evolution from pure water and seawater was investigated using mixed electron donors (sulfide and sulfite). The activity (in pure water-electron donor solution) is dependant of the modification method and loading content of NiS. When Na2S·9H2O and Na2SO3 are added into seawater, a mixture precipitate (Mg(OH)2 and CaSO3) produces. The precipitate is detrimental to the photocatalytic hydrogen evolution over the unmodified ZnS1−x−0.5yOx(OH)y–ZnO. However, for the NiS-modified photocatalyst, the detrimental effect decreases notably. Interestingly, the activity of the modified photocatalyst in seawater-electron donor solution (with the precipitate) is higher than that in the pure water-electron-donor solution (without the precipitate). The possible mechanism was discussed. [Display omitted] •ZnS1−x−0.5yOx(OH)y–ZnO as photocatalyst, NiS as co-catalyst and S2− and SO32− as electron donors.•NiS modification promotes activity of the photocatalyst for hydrogen evolution.•The activity is dependant of the modification method, and method A is better than method B.•Without NiS, the activity in seawater-ED (electron donors) is lower than that in water-ED.•With NiS modification, the activity in seawater-ED is higher than that in water-ED.