Effect of platinum loading on the photocatalytic activity and luminescence of cadmium sulfide powder

Abstract

The effect of platinum loading on the efficiency of CdS-photocatalyzed hydrogen evolution from an aqueous solution of sodium sulfite and on the intensity of the green emission (510 nm) of CdS suspended in the same solution was studied. The Fermi level of the CdS photocatalyst at the working condition can be estimated from the intensity of the green emission of the platinum-loaded CdS powder and the luminescence-potential curve of a CdS electrode. When the amount of platinum deposited on CdS is increased, the Fermi level of CdS at the working stage is moved down toward more positive potential, leading to a stronger band bending, and the photocatalytic reaction is stimulated. Too much Pt loading, however, lowers the photocatalytic activity because of the enhanced rate of electron-hole recombination as well as light absorption by platinum. The temperature effect on the reactivity and the reason for the presence of an induction period of the reaction are also elucidated in relation with the band bending of the photocatalyst.

A Facile Template‐Free Approach for the Large‐Scale Solid‐Phase Synthesis of CdS Nanostructures and Their Excellent Photocatalytic Performance

“…Although many photocatalysts capable of splitting H 2 S have been developed, most of them are oxides with a wide bandgap, which are not highly efficient photocatalysts for hydrogen production under visible‐light irradiation 31–35. Some of the metal sulfides are attractive visible‐light‐driven photocatalysts because of their narrow bandgaps with valence bands at relatively negative potentials 36–40. CdS is an attractive material which has been extensively used as a photocatalyst for degradation of organic dyes.…”

“…[31][32][33][34][35] Some of the metal sulfi des are attractive visible-light-driven photocatalysts because of their narrow bandgaps with valence bands at relatively negative potentials. [36][37][38][39][40] CdS is an attractive material which has been extensively used as a photocatalyst for degradation of organic dyes. However, reports on the usage of the material in hydrogen generation are quite limited.…”

Remarkable effect of Pt nanoparticles on visible light-induced oxygen generation from water catalysed by perovskite oxides

“…Clearly, platinum acts as a co-catalyst and promotes electron the transfer process from LaCoO3 to the dye. At high Pt loading, the activity decreases slightly due the decrease in the availability of the LaCoO3 sites for the OER [5] . From Figure 3b, we see that the rate of O2 evolution is also higher for Pt composites compared to that of LaCoO3 alone.…”

Hybrid Colloidal Heterostructures of Anisotropic Semiconductor Nanocrystals Decorated with Noble Metals: Synthesis and Function

“…[59][60][61][62][63][64][65] This research area has seen increased attention recently, with a strong focus on both revisiting Pt decoration strategies [66][67][68][69] and the development of co-catalytic systems like CdS-MoS 2 and other nanostructures. [70][71][72] Bulk CdS has conduction and valence bands at potentials appropriate for both water reduction and oxidation, and its photo-oxidation can be prevented by the use of sacrifi cial hole scavengers like sulfi des or sulfi tes.…”