Chatterjee Sauvik, Bhanja Piyali, Ghosh Dibyendu, Kumar Praveen, Kanti Das Sabuj, Dalapati Sasanka, Bhaumik Asim
School of Materials Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mallick Road, Jadavpur, Kolkata, 700032, India.
School of Technology, Department of Materials Science, Central University of Tamil Nadu (CUTN), Neelakudi, Thiruvarur, Tamil Nadu, 610005, India.
ChemSusChem. 2021 Jan 7;14(1):408-416. doi: 10.1002/cssc.202002136. Epub 2020 Oct 27.
Photoelectrochemical water-splitting offers unique opportunity in the utilization of abundant solar light energy and water resources to produce hydrogen (renewable energy) and oxygen (clean environment) in the presence of a semiconductor photoanode. Zinc oxide (ZnO), a wide bandgap semiconductor is found to crystallize predominantly in the hexagonal wurtzite phase. Herein, we first report a new crystalline triclinic phase of ZnO by using N-rich antidiabetic drug metformin as a template via hydrothermal synthesis with self-assembled nanorod-like particle morphology. We have fabricated a heterojunction nanocomposite charge carrier photoanode by coupling this porous ZnO with a covalent organic framework, which displayed highly enhanced photocurrent density of 0.62 mA/cm at 0.2 V vs. RHE in photoelectrochemical water oxidation and excellent photon-to-current conversion efficiency at near-neutral pH vis-à-vis bulk ZnO. This enhancement of the photocurrent for the porous ZnO/COF nanocomposite material over the corresponding bulk ZnO could be attributed to the visible light energy absorption by COF and subsequent efficient charge-carrier mobility via porous ZnO surface.
光电化学水分解在利用丰富的太阳能和水资源以在半导体光阳极存在的情况下产生氢气（可再生能源）和氧气（清洁环境）方面提供了独特的机会。氧化锌（ZnO）是一种宽带隙半导体，主要以六方纤锌矿相结晶。在此，我们首次报道了通过使用富含氮的抗糖尿病药物二甲双胍作为模板，通过水热合成法制备出具有自组装纳米棒状颗粒形态的新型三斜晶相ZnO。我们通过将这种多孔ZnO与共价有机框架耦合，制备了一种异质结纳米复合电荷载流子光阳极，在光电化学水氧化中，相对于可逆氢电极（RHE），在0.2 V时显示出高达0.62 mA/cm的光电流密度增强，并且在近中性pH值下相对于块状ZnO具有优异的光子到电流转换效率。多孔ZnO/共价有机框架（COF）纳米复合材料相对于相应块状ZnO的光电流增强可归因于COF对可见光能量的吸收以及随后通过多孔ZnO表面的有效电荷载流子迁移率。
