Efficient photocatalytic hydrogen evolution coupled with benzaldehyde production over 0D Cd0.5Zn0.5S/2D Ti3C2 Schottky heterojunction

Abstract

Converting water into hydrogen fuel and oxidizing benzyl alcohol to benzaldehyde simultaneously under visible light illumination is of great significance, but the fast recombination of photogenerated carriers in photocatalysts seriously decreases the conversion efficiency. Herein, a novel dual-functional 0D Cd0.5Zn0.5S/2D Ti3C2 hybrid was fabricated by a solvothermally in-situ generated assembling method. The Cd0.5Zn0.5S nano-spheres with a fluffy surface completely and uniformly covered the ultrathin Ti3C2 nanosheets, leading to the increased Schottky barrier (SB) sites due to a large contact area, which could accelerate the electron—hole separation and improve the light utilization. The optimized Cd0.5Zn0.5S/Ti3C2 hybrid simultaneously presents a hydrogen evolution rate of 5.3 mmol/(g·h) and a benzaldehyde production rate of 29.3 mmol/(g·h), which are ∼3.2 and 2 times higher than those of pristine Cd0.5Zn0.5S, respectively. Both the multiple experimental measurements and the density functional theory (DFT) calculations further demonstrate the tight connection between Cd0.5Zn0.5S and Ti3C2, formation of Schottky junction, and efficient photogenerated electron-hole separation. This paper suggests a dual-functional composite catalyst for photocatalytic hydrogen evolution and benzaldehyde production, and provides a new strategy for preventing the photogenerated electrons and holes from recombining by constructing a 0D/2D heterojunction with increased SB sites.

A novel fabrication strategy for alloyed Cd–Zn–S quantum dots–embedded glass with efficient red emission

“…From the TEM image of Cd 0.5 Zn 0.5 S solid solution in Figure 1B and corresponding size distribution from SEM image in Figure S1, aggregated particles with average particle size of 900 nm are presented. Homojunctions could be observed on the twin grain boundaries as marked with yellow circles, illustrating the coexistence of sphalerite and wurtzite phases as the sintering temperature of 980°C is not high enough for the former to be completely converted to the latter phase 34–37 . Significantly, TEM image of the corresponding QDEG sample in Figure 1C demonstrates the homogeneous distribution of Cd 0.5 Zn 0.5 S QDs–embedded within the glass matrix with an average diameter of 5 nm.…”

“…Homojunctions could be observed on the twin grain boundaries as marked with yellow circles, illustrating the coexistence of sphalerite and wurtzite phases as the sintering temperature of 980 • C is not high enough for the former to be completely converted to the latter phase. [34][35][36][37] Significantly, TEM image of the corresponding QDEG sample in Figure 1C demonstrates the homogeneous distribution of Cd 0.5 Zn 0.5 S QDs-embedded within the glass matrix with an average diameter of 5 nm. EDS elemental mappings further verify that the bright dots represent the Cd-Zn-S QDs because the particles are composed of Cd, Zn, and S elements as shown in Figure 1D.…”

The Mott–Schottky heterojunction MoC@NG@ZIS with enhanced kinetic response for promoting photocatalytic hydrogen production

“…16,18,19 Mott-Schottky heterojunctions not only improve the charge kinetics by enhancing charge separation and transfer, but also increase the reaction kinetics for redox reactions by exploiting the high activation capacity of electrocatalysts. [18][19][20][21][22] For example, the Ru-WO 2.72 Mott-Schottky heterojunction exhibited enhanced hydrogen production activity by electron redistribution. 19 Liu et al loaded metalphase ReS 2 nanosheets on BaTiO 3 nanorods via Re-O covalent bonds to form a Mott-Schottky heterojunction, which provides plentiful channels for charge transfer and achieves ultraefficient degradation of pollutants.…”

Electrocatalytic Self‐Supported‐Electrode Based on CoxNi1‐xP/TiC0.5N0.5 for Enhancing pH‐Universal Hydrogen Evolution Electrocatalysis

“…To satisfy the increasing demands for energy and alleviate environmental issues caused by fossil fuel burning, [1,2] hydrogen is regarded as a kind of non-polluted and sustainable energy elements can regulate the electronic structure of TMPs effectively to improve the physicochemical properties and adsorption energy of reaction intermediates. Co 1.49 Ni 0.51 P, [19] CoFeP, [20] CoMoP, [21] Ni 2-x Co x P, [22] NiFeP, [23] NiCoP 2 , [24] and FeMnP [25] all have good performance of HER according to relevant reports.…”

“…To satisfy the increasing demands for energy and alleviate environmental issues caused by fossil fuel burning, [ 1,2 ] hydrogen is regarded as a kind of non‐polluted and sustainable energy to substitute traditional finite fossil fuels for the main energy supply in the future. Although electrochemical water splitting has become the most important kind of method to produce hydrogen due to its low cost, no greenhouse gases emission, [ 3,4 ] high purity, and high production efficiency, [ 5 ] its development is hindered by the problem of high energy consumption and poor pH adaptability.…”