Low‐Crystalline NiS Hybridized with BiOCl Nanosheet as Highly Efficient Electrocatalyst for Dye‐Sensitized Solar Cells

Abstract

Low-crystalline nickel sulfide (NiS) nanoparticles are firstly hybridized with single-crystalline bismuth oxychloride (BiOCl) nanosheets (denoted as NiS/BiOCl) via in-situ pyrolysis of a NiCl 2 -BiCl 3 -thiourea precursor at low temperature (250°C). The idea involved is to combine the functions of low-crystalline NiS for catalyzing I 3 À to I À and BiOCl nanosheets for offering fluent charge transport pathway. Especially, in-situ hybridization leads to close assembly and strong interaction between NiS nanoparticles and BiOCl nanosheets, further enabling the synergetic electronic coupling between the two phases. As a result, the hybrid NiS/BiOCl film can catalyze the reduction of I 3 À at an extremely low charge transfer resistance of 0.21 Ω cm 2 , versus 1.63 Ω cm 2 for Pt. When used as counter electrode for dyesensitized solar cells, device using NiS/BiOCl film as counter electrode produces a high power conversion efficiency of 7.88%, versus 7.35% for Pt under the same conditions. Furthermore, low-crystalline NiS/BiOCl film can also catalyze oxygen evolution reaction with a current density of 10 mA cm À 2 at 1.61 V vs. RHE and a Tafel slope of 113 mV dec À 1 , which is potentially useful for many operational clean energy devices.Our study thus provides new opportunities for the development of highly efficient hybrid electrocatalyst in a facile and energy-saving strategy.