(619a) DFT Screening of Transition Metal-Doped CdS Catalysts for Green Hydrogen Production By H2s and H2o Splitting

Cadmium sulphide (CdS) has been extensively studied as a visible-light-active semiconductor for hydrogen evolution due to its low cost, relatively narrow band gap (around 2.4 eV) and sufficiently negative potential of conduction band edge for protons reduction[1]. Transition metal (TM) doped catalysts have recently shown better performances than pure metals and metal sulfides during operation. Therefore, we present a systematic study of catalytic activity of TM-doped (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ag, Os, Ir, Pt, and Au) CdS (110) surfaces (TM@CdS), for the H2S and H2O adsorption and dissociation, screening the best material for high-efficient hydrogen production. Spin polarized DFT-D3 calculations have been performed to gain a quantum-level understanding for the stability, electronic structures and the adsorption capacity of different CdS surfaces, validated with other experiments and computational approaches [2]. A series of descriptors including binding energies, cohesive energies, formation enegies, electronic structure (band gap and d-band center), and the reaction activity, among others, were used for screening potential candidates to process the photocatalytic hydrogen evolution reaction(see Figure).
Results indicate that most of the TM@CdS can be uniformly embedded into the CdS surface as active sites. For the HER, six types of TM (Co, Ru, Rh, Pd, Ag and Pt) @CdS show a smaller Gibbs energy of species adsorption (i.e., H2S, HS, H2O, OH, H) compared to pristine CdS surface. Compared with the existing experimental work, our study predicts that a new type of catalyst (i.e., Co@CdS) could have good performance in H2S and H2O photocatalysis. This work can reveal that compared with the pristine CdS surface, the transition metal atoms doped on CdS photocatalysts can improve the HER performance for photocatalytic H2 generation.

[1] Chem. Soc. Rev. 43 (2014) 5234–5244.
[2] Photochem. Photobiol. C Photochem. Rev. 49, (2021) 100456.