A Hierarchical MoP Nanoflake Array Supported on Ni Foam: A Bifunctional Electrocatalyst for Overall Water Splitting

Abstract

The search for an inexpensive bifunctional electrocatalyst for overall water splitting has attracted considerable research interest during the past years. Herein, self‐supported hierarchical electrodes comprising nickel foam (NF) and porous molybdenum phosphide (MoP) nanoflakes are fabricated by first growing MoO2 nanoflakes on Ni foam and then further phosphorization treatment. Remarkably, serving as both anode and cathode catalysts in a two‐electrode alkaline water‐electrolysis system, the designed electrodes only require a potential of 1.62 V to deliver a current density of 10 mA cm−2. This performance is close to that of the noble‐metal‐based electrodes, that is, integrated RuO2/Ni foam and Ni foam supported Pt/C electrodes. The low cost, facile preparation method, and desirable performance make this MoP/NF electrode a potential electrocatalyst for overall water splitting.

Hierarchical MoP Hollow Nanospheres Anchored on a N,P,S‐Doped Porous Carbon Matrix as Efficient Electrocatalysts for the Hydrogen Evolution Reaction

“…In particular, among the various promising alternatives, molybdenum phosphide (MoP) exhibits a prominent advantage owing to their similar electronic structure to Pt‐group metals . It is well recognized that the negatively charged P atoms in MoP can trap protons to serve as a “hydrogen deliverer” during HER and that the Mo−P bonds with moderate bonding can capture reaction intermediates, thus avoiding the kinetically sluggish desorption of H 2 . Nevertheless, the electrocatalytic active sites for HER are mainly derived from the metal sites at the surface with high intrinsic electronic properties, which has been confirmed by theoretical and experimental studies .…”

“…[22][23][24][25] It is well recognized that the negatively charged Pa toms in MoP can trap protons to serve as a" hydrogen deliverer" during HER and that the MoÀPb onds with moderate bondingc an capture reactioni ntermediates, thus avoidingt he kinetically sluggish desorption of H 2 . [22,26] Nevertheless,t he electrocatalytic active sites for HERare mainly derived from the metal sites at the surface with high intrinsic electronic properties, which has been confirmed by theoreticala nd experimental studies. [27,28] Therefore, construction of MoP electrocatalysts with sufficient exposed active sites is currentlyamajor researchf ocal point and design strategy.…”

“…As shown in the X‐ray diffraction (XRD) pattern of hs ‐MoP/NPSC (Figure b), all peaks can be unambiguously indexed to the hexagonal crystalline phase of MoP (JCPDS No. 24‐0771), and no other peaks are identified. However, the samples prepared without both petroleum asphalt and g‐C 3 N 4 display typical peaks of MoP 2 O 7 (JCPDS No.…”

“…Furthermore, the HER kinetics have been disclosed by using the Tafel plots, as illustrated in Figure c. Here, Pt/C exhibits the lowest Tafel slope of 33 mV dec −1 , suggesting that the Tafel reaction is the rate‐limiting step . By contract, the Tafel slope of hs ‐MoP/NPSC‐0.3 is 87.2 mV dec −1 , which is noticeably lower than those of other hs ‐MoP/NPSC counterparts, indicating a Volmer–Heyrovsky mechanism with the hydrogen desorption reaction as the rate‐determining step . The smaller Tafel slope suggests the faster HER rate with a decrease in overpotential.…”

A Self‐Assembled Flower‐Like Structure of Nickel‐Cobalt Phosphide Nanosheets Supported on Nickel Foam for Electrochemical Hydrogen Evolution Reaction

“…These overpotentials compare favorably to most reported non‐noble‐metal HER catalysts in the corresponding media. Furthermore, cobalt phosphides, molybdenum phosphides and tungsten phosphides were investigated as efficient catalysts for HER. Liu et al.…”