物理化学学报2022，Vol.38Issue(7)：36-44,9.DOI:10.3866/PKU.WHXB202110049
Ni2P-NiS双助剂促进g-C3N4光催化产氢动力学
Enhancement of Photocatalytic H2-Evolution Kinetics through the Dual Cocatalyst Activity of Ni2P-NiS-Decorated g-C3N4 Heterojunctions
摘要
Abstract
With rapid industrialization,issues pertaining to the environment and energy have become an alarming concern.Photocatalytic water splitting is considered one of the most promising green technologies capable of resolving these issues,as it can convert solar energy into chemical energy and have a positive impact on the realization of"carbon neutrality".Current research focuses on the development of highly efficient catalysts to improve the photocatalytic H2-production activity.Transition metal phosphides and sulfides are often used as photocatalysts owing to their low H2-evolution overpotential and excellent electrical conductivity.Among them,Ni2P and NiS have generally been used independently during photocatalytic H2 production;however,it is necessary to study the synergistic effect when they are combined as a dual cocatalyst.In this work,we successfully prepared a Ni2P-NiS dual cocatalyst for the first time via a simple hydrothermal method using red phosphorus(RP)and thioacetamide(C2H5NS)as the sources of P and S.Ni2P-NiS was then introduced to the surface of g-C3N4 nanosheets through solvent evaporation to create a Ni2P-NiS/g-C3N4 heterojunction.Furthermore,X-ray diffraction(XRD),scanning electron microscope(SEM),transmission electron microscope(TEM),ultraviolet-visible spectrophotometry(UV-Vis),X-ray photoelectron spectroscopy(XPS),photoluminescence(PL),linear sweep voltammetry(LSV),Mott-Schottky(M-S),and electrochemical impedance spectroscopy(EIS)were used to reveal the crystal structures,morphologies,element compositions,and photoelectric characteristics of the samples;thus,it was demonstrated that Ni2P-NiS was successfully deposited on the surface of g-C3N4 and that together they exhibited better activity than their monomers.Moreover,the optimized 15％Ni2P-NiS/g-C3N4 composite exhibits a H2 generation rate of 6892.7 μmolg-1h-1,which is about 46.1,7.5 and 4.4 times higher than that of g-C3N4(150 μmol·g-1·h-1),15％NiS/g-C3N4(914.5 μmolg-1·h-1),and 15％Ni2P/g-C3N4(1565.9 μmol·g-1·h-)),respectively.In addition,photoelectric performance tests show that Ni2P-NiS/g-C3N4 has a stronger photocurrent intensity,smaller charge-transfer resistance,more positive H2-evolution overpotential,and better charge-separation ability than the individual components(i.e.,Ni2P and NiS),suggesting that the coexistence of Ni2P and NiS can further boost the activity of g-C3N4 during H2 evolution compared with their monomers.This is mainly due to the Schottky barrier effect between Ni2P-NiS nanoparticles and g-C3N4 nanosheets,which can greatly promote charge separation and charge transfer at their interface.Additionally,Ni2P-NiS can reduce the H2-evolution overpotential,leading to the increased surface kinetics of H2 evolution.This work offers a promising approach to obtaining a highly active and stable noble-metal-free dual cocatalyst for photocatalytic H2 production.关键词
Ni2P-NiS/g-C3N4/助催化剂/肖特基结/光催化分解水Key words
Ni2P-NiS/g-C3N4/Cocatalyst/Schottky barrier/Photocatalytic water splitting分类
化学化工引用本文复制引用
雷卓楠,马心怡,胡晓云,樊君,刘恩周..Ni2P-NiS双助剂促进g-C3N4光催化产氢动力学[J].物理化学学报,2022,38(7):36-44,9.基金项目
This work was supported by the National Natural Science Foundation of China(21676213,11974276,22078261),Natural Science Basic Research Program of Shaanxi(2020JM-422).国家自然科学基金(21676213,11974276,22078261),陕西省自然科学基础研究计划项目(2020JM-422)资助 （21676213,11974276,22078261）
