A Full-Spectrum ZnS Photocatalyst with Gradient Distribution of Atomic Copper Dopants and Concomitant Sulfur Vacancies for Highly Efficient Hydrogen Evolution

Abstract

A rarely discussed phenomenon in the realm of photocatalytic materials involves the presence of gradient distributed dopants and defects from the interior to the surface. This intriguing characteristic has been successfully achieved in the case of ZnS through the incorporation of atomic monovalent copper ions (Cu + ) and concurrent sulfur vacancies (V s ), resulting in a photocatalyst denoted as G-CZS 1−x . Through the cooperative action of these atomic Cu dopants and Vs, G-CZS 1−x significantly extends its photoabsorption range to encompass the full spectrum (200−2100 nm), which improves the solar utilization ability. This alteration enhances the efficiency of charge separation and optimizes Δ(H*) (free energy of hydrogen adsorption) to approach 0 eV for the hydrogen evolution reaction (HER). It is noteworthy that both surface-exposed atomic Cu and V s act as active sites for photocatalysis. G-CZS 1−x exhibits a significant H 2 evolution rate of 1.01 mmol h −1 in the absence of a cocatalyst. This performance exceeds the majority of previously reported photocatalysts, exhibiting approximately 25-fold as ZnS, and 5-fold as H-CZS 1−x with homogeneous distribution of equal content Cu dopants and Vs. In contrast to G-CZS 1−x , the H adsorption on Cu sites for H-CZS 1−x (ΔG(H*) = −1.22 eV) is excessively strong to inhibit the H 2 release, and the charge separation efficiency for H-CZS 1−x is relatively sluggish, revealing the positive role of a gradient distribution model of dopants and defects on activity enhancement. This work highlights the synergy of atomic dopants and defects in advancing photoactivity, as well as the significant benefit of the controllable distribution model of dopants and defects for photocatalysis.

Construction of an In2O3/Bi2S3 Z-Scheme Heterojunction for Enhanced Photocatalytic CO2 Reduction

“…The photoinduced charge separation and transfer efficiency of photocatalysts affect the number of charges participating in the photocatalytic reaction, which is of great importance to the photocatalytic activity. , As shown in Figure a,b, IOBS-3 exhibits a remarkably better photocurrent density of transient photocurrent response curve and linear sweep voltammetry (LSV) curves than that of Bi 2 S 3 and In 2 O 3 , indicating the improved charge separation efficiency of IOBS-3. − In the electrochemical impedance spectroscopy (EIS) Nyquist plots (Figure c), IOBS-3 has a smaller arc radius to Bi 2 S 3 and In 2 O 3 , suggesting the higher charge transfer efficiency of IOBS-3 . In Figure S10, the PL and PLE intensities of IOBS-3 are significantly lower than In 2 O 3 , revealing the lower charge recombination rate of IOBS-3 .…”

Evaluation of zinc sulfide heterostructures as catalysts for the transformation of CO2 into valuable chemicals and clean energy generation

“…135 Likewise, ZnS/ZnO heterostructures have exhibited commendable stability in continuous flow reactors, underscoring their potential for scalability in industrial applications. 136 Future research efforts are poised to deepen the understanding of factors influencing ZnS catalyst stability. Utilization of advanced in situ characterization techniques, such as X-ray diffraction (XRD) and electron microscopy, will allow real-time monitoring of structural transformations in ZnS catalysts during operational deployment.…”

ReS2/CdIn2S4–SV Heterojunctions for Photocatalytic Hydrogen Production

“…In particular, creating surface sulfur vacancies (S V ) in chalcogenides has proven to be an effective strategy to promote the separation of photogenerated charge carriers. , Bao et al skillfully incorporated monovalent copper ions (Cu + ) into ZnS, concurrently generating sulfur vacancies (S V ), thereby achieving an efficient synergistic interaction between atomic Cu and S V . This strategy not only designated the surface-exposed atomic Cu and sulfur vacancies as key active sites for photocatalytic reactions but also substantially broadened the light absorption spectrum of G-CZS 1– x across the entire range (200–2100 nm), significantly enhancing solar energy conversion efficiency . Therefore, employing versatile modification strategies or a combination of multiple modification approaches constitutes an effective pathway for achieving comprehensive modification of materials.…”