RESUMO
Inspired by energy conversion and waste reuse, hybridized Ni-MOF derivative-CdS-DETA/g-C3N5, a type-II heterojunction photocatalyst, is synthesized by a hydrothermal method for simultaneous and highly efficient photocatalytic degradation and hydrogen evolution in dye wastewater. Without the addition of cocatalysts and sacrificial agents, the optimal MOF-CD(2)/CN5 (i.e. Ni-MOF derivative-CdS-DETA (20 wt.%)/g-C3N5) exhibit good bifunctional catalytic activity, with a H2 evolution rate of 2974.4 µmol g-1 h-1 during the degradation of rhodamine B (RhB), and a removal rate of 99.97% for RhB. In the process of H2-evolution-only, triethanolamine is used as a sacrificial agent, exhibiting a high H2 evolution rate (19663.1 µmol g-1 h-1) in the absence of a cocatalyst, and outperforming most similar related materials (such as MOF/g-C3N5, MOF-CdS, CdS/g-C3N5). With the help of type-II heterojunction, holes are scavenged for the oxidative degradation of RhB, and electrons are used in the decomposition of water for H2 evolution during illumination. This work opens a new path for photocatalysts with dual functions of simultaneous efficient degradation and hydrogen evolution.
RESUMO
A novel ternary photocatalyst Ni3S4@ZIS@C3N5 with type II and Z-type heterojunctions was synthesized for the first time by hydrothermal and electrostatic self-assembly methods, effectively avoiding the thermal decomposition of C3N5 during the synthesis of the complex. The best ternary catalyst Ni3S4@ZIS@C3N5 is capable of achieving an optimal hydrogen evolution rate of 9750 mmol g-1 h-1, which is approximately 10.89 times as high as that of C3N5, indicating that the complex effectively enhanced the photocatalytic properties of the monomer. The coexistence of two types of heterojunctions in the complex effectively enhances photocatalytic performance, in which the monomer ZIS constructs type II scheme with Ni3S4 and Z-type scheme with C3N5, respectively. The two heterojunctions complement each other and jointly promote the rapid electron transfer from Ni3S4 and C3N5 to the ZIS surface. In conclusion, the cooperation of the two heterojunctions efficiently facilitates the migration of photogenerated carriers, thus enhancing the photocatalytic hydrogen generation performance of Ni3S4@ZIS@C3N5.
Assuntos
HidrogênioRESUMO
An abundant supply of fresh water is one of the leading challenges of the 21st century (UNESCO. The United Nations World Water Development Report 2018: Nature-Based Solutions for Water;UNESCO: Paris, France, 2018; p 154). Here we describe a new approach to scavenge atmospheric water that employs a hierarchically ordered porous material with embedded particles (Lash, M. H.; Jordan, J. C.; Blevins, L. C.; Fedorchak, M. V.; Little, S. R.; McCarthy, J. J.Non-Brownian Particle-Based Materials with Microscale and Nanoscale Hierarchy. Ang. Chem. Int. Ed.201554, 5854-5858). This composite uses structure to amplify native material performance to realize synergy between the capture and storage and to ultimately qualitatively change the adsorption behavior of the hydrogel (from unfavorable to favorable). In this way we can capture moisture at significantly lower relative humidities than would otherwise be feasible with the native materials. Not only does this approach pose the potential for a cheap and low-energy source of clean water but it could also be modified for application across a variety of condensable vapor reclamations.