Hierarchically Porous Carbonized Wood Decorated with MoNi₄‐Embedded MoO₂ Nanosheets: An Efficient Electrocatalyst for Water Splitting

Abstract

Development of low‐cost electrocatalysts for water splitting is crucial to economical hydrogen production. Here, a highly efficient electrocatalyst composed of MoNi4‐embedded amorphous MoO2 nanosheets grown on less‐tortuosity hierarchically porous carbonized wood (MoNi4/MoO2@CW) is reported. The generation of abundant MoNi4/MoO2 heterointerfaces and defects‐rich MoO2 significantly promote the adsorption and activation of reactant molecules on the MoNi4/MoO2@CW. The obtained MoNi4/MoO2@CW catalyst exhibits ultralow overpotentials of 22 and 205 mV for hydrogen evolution reaction and oxygen evolution reaction at a current density of 10 mA cm−2, respectively. The catalyst can be used for dual‐function electrodes and assembling two‐electrode electrolyzer illustrates 10 mA cm−2 at 1.47 V and superior durability over 24 h for overall water electrolysis. Moreover, it also possesses a high mass activity of 142 Ag−1 MoNi4 at 200 mV, surpassing the Pt/C catalyst (132 Ag−1). The outstanding performance of the MoNi4/MoO2@CW is attributed to the decrease in energy barrier for water dissociation, optimal adsorption/desorption of H/O‐intermediates, and fast mass transport through the porous structure, as confirmed by experimental results and density functional theory‐based calculations. The MoNi4/MoO2@CW electrocatalyst has excellent potential for practical water splitting.

Sub‐2 nm IrRuNiMoCo High‐Entropy Alloy with Iridium‐Rich Medium‐Entropy Oxide Shell to Boost Acidic Oxygen Evolution

“…[23,31] However, with the etching time increases, the metallic state of Co, Ni, and Mo can be found and the intensities of XPS profiles gradually increase (Figure S6, Supporting Information). [15,32] Above results definitely corroborate that the surface of HEA@Ir-MEO is composed of Ir-rich IrRuNiMo medium-entropy oxides (Ir-MEO), while the interior is composed of the IrRuCoNiMo high-entropy alloy, thereby constructing the unique core-shell structure.…”

The Electrocatalytic Oxygen Evolution Reaction Activity of Rationally Designed NiFe-Based Glycerates

“…The XPS spectrum of Ni 2p deconvoluted into the four peaks, as shown in Figure 3a. The fitting peaks located at ~855.78 and ~873.68 eV corresponded to the Ni 2p 3/2 (Ni 2+ ) and Ni 2p 1/2 (Ni 2+ ), respectively [28]. The other two nickel satellite peaks were also observed at ~861.58 and ~879.78 eV, respectively [29].…”

Rise of wood-based catalytic electrodes for large-scale hydrogen production

“…The specific surface area of wood-based catalysts, indicating the quantity of active sites, can be measured using techniques like nitrogen adsorption–desorption. For instance, Mao et al 103 prepared a MoNi 4 /MoO 2 @CW catalytic electrode which exhibited a large specific surface area of 143 m 2 g −1 (Fig. 10a), attributed to its hierarchical nano-porous structure.…”