Ternary compound heterojunction from isomerism h-CdS/c-CdSe exhibits boosting photoelectrochemical and hydrogen evolution reaction properties.

A novel h-CdS/c-CdSe ternary compound heterojunction catalyst CdSS is constructed from isomerism hexagonal CdS and cubic CdSe. The isomerism hexagonal CdS and cubic CdSe is the key factor to obtain the CdSS heterojunction, as compared, ternary compound CdSSe can only be prepared from isomorphic hexagonal CdS and hexagonal CdSe. Under different S:Se ratio, the main XRD peaks of CdSS displayed continuous shift between related CdS and CdSe peaks that confirms the S and Se atoms embedding CdSe and CdS lattice respectively to form atomic level ternary compound heterojunction. The photoelectrochemical and electrocatalytic results show that the CdSS catalysts have boosting properties. Under an optimal S:Se ratio, the photocurrent density of the CdSS reach 8.23 μA/cm2, which was 4.5 times that of original CdS (1.83 μA/cm2), 4.9 times of CdSe (1.67 μA/cm2) and 5.1 times of CdSSe (1.60 μA/cm2). The hydrogen evolution reaction Tafel slope of CdSS also declined 60% compared with CdS and 64% compared with CdSe. The electrocatalytic impedance and fluorescence spectra fully show that CdSS has lower internal resistance and low electron-hole recombination efficiency due to the atomic level heterojunction. The work develops a new strategy to construct high efficiency atomic level ternary compound heterojunction between isomerism homologous element compounds. A novel h-CdS/c-CdSe ternary compound heterojunction catalyst CdSS is constructed from isomerism hexagonal CdS and cubic CdSe. The isomerism hexagonal CdS and cubic CdSe is the key factor to obtain the CdSS heterojunction. [Display omitted] • A novel h-CdS/c-CdSe heterojunction catalyst CSS is constructed from isomerism h-CdS and c-CdSe. • The isomerism h-CdS and c-CdSe is the key factor to obtain the h-CdS/c-CdSe heterojunction. • A isomorphic ternary compound CdSSe is compared from isomorphic h-CdS and h-CdSe. • The isomerism CSS is conformed to has the highest PEC and HER performance. • The high carrier separation heterojunction is formed between h-CdS and c-CdSe. [ABSTRACT FROM AUTHOR]