Long Xuefeng, Li Feng, Gao Lili, Hu Yiping, Hu Haiguo, Jin Jun, Ma Jiantai
State Key Laboratory of Applied Organic Chemistry (SKLAOC), The Key Laboratory of Catalytic Engineering of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu, 730000, P. R. China.
ChemSusChem. 2018 Dec 11;11(23):4094-4101. doi: 10.1002/cssc.201801828. Epub 2018 Oct 30.
Application of ZnO in the field of photoelectrochemical water splitting is limited because of its wide-band-gap and high recombination rate. Herein is reported the design of an efficient ZnO photoanode deposited with CoO nanoparticles to achieve a heterojunction and oxygen vacancies. The CoO nanoparticles with abundant oxygen vacancies were anchored onto the nanorod arrays by spin coating and calcination followed by a solvothermal treatment. CoO nanoparticles serve the dual function of forming a p-n heterojunction to facilitate the separation of photogenerated carriers, and act as a cocatalyst to decrease water oxidation barrier. Finally, oxygen vacancies increase the number of active redox sites and act as hole traps, enabling their migration to the electrode/electrolyte interface. The composite photoanode exhibits a high incident photon-to-current conversion efficiency (76.7 % at 350 nm), which is twice that of pristine ZnO, and a photoconversion efficiency of 0.68 % (0.73 V versus RHE). The current approach can be expanded to fabricate other efficient photocatalysts.
由于ZnO的宽带隙和高复合率，其在光电化学水分解领域的应用受到限制。本文报道了一种通过沉积CoO纳米颗粒来设计高效ZnO光阳极的方法，以实现异质结和氧空位。通过旋涂、煅烧，然后进行溶剂热处理，将具有丰富氧空位的CoO纳米颗粒锚定在纳米棒阵列上。CoO纳米颗粒具有双重功能，既形成p-n异质结以促进光生载流子的分离，又作为助催化剂降低水氧化势垒。最后，氧空位增加了活性氧化还原位点的数量，并充当空穴陷阱，使其能够迁移到电极/电解质界面。该复合光阳极表现出较高的入射光子-电流转换效率（在350 nm处为76.7 %），是原始ZnO的两倍，光转换效率为0.68 %（相对于可逆氢电极的电势为0.73 V）。目前的方法可以扩展到制备其他高效光催化剂。
