Preparation of p-n heterojunction with NiWO4 and Co-based bimetallic oxide and its photocatalytic hydrogen evolution performance

Abstract

Bimetallic oxides have attracted extensive attention due to their excellent photocatalytic properties. Co 2 NiO 4 has good electrical activity which can effectively regulate the distribution of charge. The scanning electron microscope and transmission electron microscope images of Co 2 NiO 4 showed two-dimensional uniform lamellar morphology. This kind of morphology could provide a larger specific surface area, which was conducive to improving photocatalytic water decomposing and hydrogen evolution. In addition, we combined Co 2 NiO 4 with NiWO 4 to improve the conductivity of Co 2 NiO 4 and the position of Fermi energy level, forming a p-n-type heterojunction, effectively promoting the interface charge transfer through the internal electric field, and inhibiting the electron-hole pair recombination. The photocatalytic hydrogen production of CN/NW-3 in the sensitized system reached 341.83 lmol for 5 h, which was 19 times that of pure Co 2 NiO 4 . At the same time, UV-Vis diffuse reflection and Mott-Schottky curve were used to further determine the conduction band (CB) and valence band (VB) positions of Co 2 NiO 4 and NiWO 4 , which formed a charge transport path with higher separation and transfer efficiency. This work highlights the high-efficient photocatalytic hydrogen production performance of CN/NW p-n heterojunction.

Hydrogen evolution performance of Co-MOF/H-g-C3N4 composite catalysts with different morphologies under visible light

“…By converting the Ag/AgCl electrode to the H 2 /H + electrode, the conduction band position can be obtained from the flat band potential. 76–79 The conduction potential of H-g-C 3 N 4 is −0.22 eV. The conductance potential of Co-MOF-B is −0.9 eV.…”

Synthesis of Ternary MoS2/Carbon Dots/ZnIn2S4 Nanocomposites for Enhanced Photocatalytic Hydrogen Evolution

“…The utilization of semiconductor photocatalysts for solar-driven hydrogen production is regarded as a promising and environmentally friendly strategy to tackle the escalating energy and environmental crises resulting from the excessive consumption of fossil fuel. − Since the groundbreaking work of Fujishima and Honda on photoelectrochemical (PEC) cells, which utilized a TiO 2 -loaded Pt electrode for hydrogen evolution, considerable efforts have been dedicated to the advancement of hydrogen evolution photocatalysts . Over the past 2 decades, there has been significant progress in the development of inorganic semiconductors, encompassing metal oxides, metal sulfides, nitrogen oxides, and certain metal-free semiconductors like g-C 3 N 4 , tailored for visible light-driven hydrogen evolution. − Among various photocatalysts, ZnIn 2 S 4 (referred to as ZIS), a ternary sulfide, stands out as a typical visible light-driven semiconductor owing to its suitable band structure, broad light absorption range, nontoxicity, and good photostability for water reduction to hydrogen. − In particular, flower-like ZIS nanospheres often exhibit much higher photocatalytic activity than nanoparticles, attributed to the rich active sites provided by the nanoflower structure, promoting the separation of charge carriers and significantly enhancing photocatalytic performance . However, the hydrogen evolution photocatalytic activity of ZIS is often unsatisfactory due to rapid light-induced carrier recombination and inevitable photocorrosion during the photoreaction process. , Therefore, constructing heterostructures by coupling ZIS with other semiconductors possessing matched band structures and corrosion resistance can be employed to achieve effective charge carrier separation and improve photostability.…”

Nickel aluminum oxide hydrate supports ZIF-67 with different morphologies to achieve the improvement of photocatalytic hydrogen production performance

“…The excellent chemical reaction properties exhibited by the composite catalysts were investigated in electrochemical experiments. [35][36][37][38] The highly efficient hydrogen production results powerfully demonstrate the applicability of Ni 5 Al 4 O 11 Á 18H 2 O/ZIF-67 composites. In this paper, the photocatalytic materials are extended to organic-inorganic composite systems, and the reduction ability and transfer rate of electrons are improved.…”