Enhanced Electrocatalytic Water Oxidation by Interfacial Phase Transition and Photothermal Effect in Multiply Heterostructured Co₉S₈/Co₃S₄/Cu₂S Nanohybrids

Abstract

The rational design of advanced nanohybrids (NHs) with optimized interface electronic environment and rapid reaction kinetics is pivotal to electrocatalytic schedule. Herein, we developed a multiple heterogeneous Co9S8/Co3S4/Cu2S nanoparticle in which Co3S4 germinates between Co9S8 and Cu2S. Using high‐angle annular‐dark‐field imaging and theoretical calculation, it was found that the integration of Co9S8 and Cu2S tends to trigger the interface phase transition of Co9S8, leading to Co3S4 interlayer due to the low formation energy of Co3S4/Cu2S (−7.61 eV) than Co9S8/Cu2S (−5.86 eV). Such phase transition not only lowers the energy barrier of oxygen evolution reaction (OER, from 0.335 eV to 0.297 eV), but also increases charge carrier density (from 7.76×1014 to 2.09×1015 cm−3), and creates more active sites. Compared to Co9S8 and Cu2S, the Co9S8/Co3S4/Cu2S NHs also demonstrate notable photothermal effect that can heat the catalyst locally, offset the endothermic enthalpy change of OER, and promote carrier migrate, reaction intermediates adsorption/deprotonation to improve reaction kinetics. Profiting from these favorable factors, the Co9S8/Co3S4/Cu2S catalyst only requires an OER overpotential of 181 mV and overall water splitting cell voltage of 1.43 V to driven 10 mA cm−2 under the irradiation of near‐infrared light, outperforming those without light irradiation and many reported Co‐based catalysts.

An enhanced electrocatalytic oxygen evolution reaction by the photothermal effect and its induced micro-electric field

“…In addition to modifying the electronic structure of electrocatalysts, achieving enhanced strategies for electrocatalysis using the temperature field generated by the photothermal effect has become an interesting topic in recent years. 37–41 From the Arrhenius law , the catalytic reaction temperature ( T ) could be known to have a vital influence on the reaction rate ( k ). 42 Electrodes with photo-thermal conversion capability are able to directly utilize energy from renewable solar energy and be heated, which provides a novel strategy to achieve an efficient and economical electrocatalytic reaction.…”

Floatable Cu2(OH)PO4/rGO Aerogel for Full Spectrum Driven Photocatalytic Degradation of Organic Pollutants

“…Designing a heterostructure system with a wide light-absorption range and efficient charge carrier mobility is essential for achieving full spectrum solar light utilization . From the aspect of light absorption, narrow bandgap semiconductors such as Cu 2 (OH)­PO 4 , Cu 2 S, Ag 2 S, and BiWO 6 with NIR response are promising to achieve full spectrum absorption. Unfortunately, narrow bandgap semiconductors suffer from low carrier separation efficiency and short carrier lifetime due to the limitation of Coulombic interactions between electrons and holes, limiting the light utilization efficiency. , Very recently, low-dimensional heterostructures including 0D/2D, 1D/2D, and 2D/2D systems , have gained popularity due to the short-range interfacial interaction of two low-dimensional materials, which can promote electronic coupling and electron transfer.…”

Bird Nest-Like Fe3O4/CoOx Nanosphere Heterojunctions with Amorphous/Crystalline Structure for Enhanced Electrochemical Oxygen Evolution

“…Hydrogen production by water electrolysis features the merits of high safety, good stability, and high efficiency. − However, as the core process in the semireaction of electrolytic water, OER is a typical four-electron reaction (4OH – → O 2 + 2H 2 O + 4e – ) in alkaline solution which has sluggish reaction kinetics, so it is necessary to develop efficient OER electrocatalysts. − Although RuO 2 and IrO 2 have good OER catalytic activity, they are very expensive, and the noble metal oxides are easily oxidized to higher valence states and dissolved in solution at higher anode overpotential. − To this end, it is urgent to design a low-cost, high-efficient, and stable OER electrocatalyst . In recent years, it has been found that transition metal-based electrocatalysts such as oxides, , hydroxides, , selenides, − sulfides, − nitride and phosphates − show great advantages in electrocatalysis. Among them, transition metal oxides (TMOs) are potential alternatives to replace noble metal oxides for the OER which have the advantages of abundant reserves, cheap and easy to obtain, flexible valence state, and friendly to the environment.…”