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

Abstract

AbstractLow‐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 NiCl2‐BiCl3‐thiourea precursor at low temperature (250 °C). The idea involved is to combine the functions of low‐crystalline NiS for catalyzing I3− to I− 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 I3− at an extremely low charge transfer resistance of 0.21 Ω cm2, versus 1.63 Ω cm2 for Pt. When used as counter electrode for dye‐sensitized 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−2 at 1.61 V vs. RHE and a Tafel slope of 113 mV dec−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.