Highly Efficient Photocatalysts: Polyoxometalate Synthons Enable Tailored CdS–MoS₂ Morphologies and Enhanced H₂ Evolution

Abstract

The development of photocatalysts toward highly efficient H2 evolution reactions is a feasible strategy to achieve the effective conversion of solar energy and meet the increasing demand for new energy. To this end, we prepared two different CdS–MoS2 photocatalysts with unique morphologies ranging from hexagonal prisms to tetragonal nanotubes by carefully tuning polyoxometalate synthons. These two photocatalysts, namely, CdS–MoS2-1 and CdS–MoS2-2, both exhibited remarkable photocatalytic efficiency in H2 generation, among which CdS–MoS2-2 showed superior performance. In fact, the best catalytic hydrogen desorption rate of CdS–MoS2-2 is as high as 1815.5 μmol g–1 h–1. Such performance is superior to twice that of single CdS and almost four times that of pure MoS2. This obvious enhancement can be accredited to the highly open nanotube morphology and highly dispersed heterometallic composition of CdS–MoS2-2, which represents an excellent example of the highest noble-metal-free H2 evolution photocatalysts reported so far. Taken together, these findings suggest that the development of highly dispersed heterometallic catalysts is an auspicious route to realize highly efficient conversion of solar energy and that CdS–MoS2-2 represents a major advance in this field.

Multi‐Dimensional Binary Micro CuCo2O4/Nano NiCo2S4 for High‐Performance Supercapacitors

“…CV measurements of CCO and NCS were carried out under different sweep speeds (Figure S5). By observing the image, it can be clearly seen that the CV curve of CCO has a pair of redox peaks in the potential window range of 0–0.45 V, indicating that the specific capacitance is mainly provided by the redox reactions of Co 2+ /Co 3+ /Co 4+ and Cu 2+ /Cu + with OH − ions, which are represented as follows: [2,35] $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {\rm CuCo}{_{2}}{\rm O}{_{4}}+{\rm 2H}{_{2}}{\rm O}+{\rm e}{^{- }}\leftrightarrow {\rm 2CoOOH}+{\rm CuOH}+{\rm OH}{^{- }}\hfill\cr}}$$$ $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {\rm CoOOH}+{\rm OH}{^{- }}\leftrightarrow {\rm CoO}{_{2}}+{\rm H}{_{2}}{\rm O}+{\rm e}{^{- }}\hfill\cr}}$$$ $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {\rm CuOH}+{\rm OH}{^{- }}\leftrightarrow {\rm Cu}({\rm OH}){_{2}}+{\rm e}{^{- }}\hfill\cr}}$$$ …”

“…CV measurements of CCO and NCS were carried out under different sweep speeds (Figure S5). By observing the image, it can be clearly seen that the CV curve of CCO has a pair of redox peaks in the potential window range of 0-0.45 V, indicating that the specific capacitance is mainly provided by the redox reactions of Co 2 + /Co 3 + /Co 4 + and Cu 2 + /Cu + with OH À ions, which are represented as follows: [2,35] CuCo…”

“…As a promising rechargeable energy storage device, supercapacitors have attracted tremendous attention due to the excellent charge storage capacity, fast recharge ability, high power density and long service life [1–4] . The preparation of electrode materials with excellent electrochemical performance is the key factor to obtain high energy density supercapacitor.…”

“…As a promising rechargeable energy storage device, supercapacitors have attracted tremendous attention due to the excellent charge storage capacity, fast recharge ability, high power density and long service life. [1][2][3][4] The preparation of electrode materials with excellent electrochemical performance is the key factor to obtain high energy density supercapacitor. Recently, binary transition metal oxides (BTMO), such as CuCo 2 O 4 , [5] ZnCo 2 O 4 [6] and NiMoO 4 [7] have been considered to be the promising candidates as electrodes owing to their multiple redox reactions and high electrical conductivity.…”

Transformation of a Polyoxometalate Precursor into Carbon Doped Bismuth Molybdate Nanosheets for the Visible Light Photocatalytic Degradation of Aqueous Pollutants

“…For example, Ran et al developed a Si-doped ZnWO 4 @ZnO photocatalyst with a unique morphology from a Keggin POMs@ZIF precursor that acted as an efficient catalyst for degrading Rhodamine B under visible light irradiation . Recently, Sun et al reported the synthesis of CdS-MoS 2 with different morphologies under different synthetic conditions starting from the H 3 PMo 12 O 40 cluster and studied the effects of morphology on their photocatalytic hydrogen evolution activities . These new photocatalysts showed superior performance toward the hydrogen evolution reaction (HER) compared to the conventional CdS.…”