CoMo₂S₄ with Superior Conductivity for Electrocatalytic Hydrogen Evolution: Elucidating the Key Role of Co

Abstract

CoMo2S4 2D nanosheets are constructed by a hard template‐limited domain strategy, meanwhile the hydrogen evolution reaction (HER) properties and the function of Co in CoMo2S4 are systematically investigated. Electrochemical tests show that CoMo2S4 possesses high HER performance with an overpotential of 55 and 150 mV at 10 and 100 mA cm−2, respectively, outperforming Pt/C (20%) and the state of art Mo–S, Co–S, and Co–Mo–S‐based materials. An in‐depth mechanism study reveals that the main active site of CoMo2S4 is Mo rather than Co, whereas Co plays a key role in improving the electrical conductivity of the catalyst and thus improving the HER performance. X‐ray photoelectron spectroscopy and density of state tests demonstrate that the introduction of Co leads to electron delocalization in the catalyst, making the electrons transport easier and finally endowing the catalyst with better conductive performance. It is believed this is the first time that the effect of Co on improving the bulk conductivity of Co–Mo–S catalyst is proposed, which highlights the potency of Co in improving the electrocatalytic HER activity of Mo–S‐based materials.

Hierarchical CoMoS3.13/MoS2hollow nanosheet arrays as bifunctional electrocatalysts for overall water splitting

“…31,32 However, CoMoS x structures always stack together, burying many reactive sites, which has an adverse effect on the overall catalytic activity. 33,34 Consequently, tremendous effort has been made to exploit various kinds of CoMoS x morphologies, such as CoMoS 4 nanoflowers, 35,38 CoMoS x 2D nanosheets, 36,37 and CoS 2 -MoS 2 hollow spheres or nanosheets. 39,40 Among these, hollow structures have received great attention, as they possess distinguishable interior voids and thin shells that lead to large specific surface areas, abundant chemical reaction sites, remarkable cycling capabilities, and high diffusion efficiencies, thus leading to prominent electrochemical performance.…”

Reactive template-engaged synthesis of Ni-doped Co3S4 hollow and porous nanospheres with optimal electronic modulation toward high-efficiency electrochemical oxygen evolution

“…The dominant two peaks located at 161.2 and 162.3 eV are attributed to S 2p 3/2 and S 2p 1/2 , respectively, while the remaining peak at 168.7 eV corresponds to the sulfate/sulfite species due to the surface oxidation of S 2− exposed to air. 48,49 As mentioned above, the self-sacrificial reactive templateengaged strategy allows the compositional tuning of the obtained Ni-Co 3 S 4 samples by simply altering the Ni/Co molar ratios in the feeding precursors, which offers a powerful handle to optimize the electrocatalytic performance of these functional materials. The compositional and morphological characterization of the pristine Co 3 S 4 , Ni-Co 3 S 4 -1 and Ni-Co 3 S 4 -3 samples is carried out using SEM and XRD measurements (Fig.…”

“…The dominant two peaks located at 161.2 and 162.3 eV are attributed to S 2p 3/2 and S 2p 1/2 , respectively, while the remaining peak at 168.7 eV corresponds to the sulfate/sulfite species due to the surface oxidation of S 2− exposed to air. 48,49…”

Size-controlled, hollow and hierarchically porous Co2Ni2 alloy nanocubes for efficient oxygen reduction in microbial fuel cells

“…An in-depth analysis of the large hexagonal diffraction pattern demonstrated a crystal plane distance of 0.213 nm, which can be assigned to the (111) crystal plane of the Co 2 Ni 2 alloy. 38,39 The STEM-EDS line-scanning profiles of the central regions of the intact nanocubes for the Co 2 Ni 2 ANCs and HANCs are shown in Fig. S8† and the corresponding results are shown in Fig.…”