NiFeMo alloy inverse-opals on Ni foam as outstanding bifunctional catalysts for electrolytic water splitting of ultra-low cell voltages at high current densities

Molybdenum and Phosphorous Dual‐Doped, Transition‐Metal‐Based, Free‐Standing Electrode for Overall Water Splitting

“…Apart from that, the incorporation of Mo (in the G-3 and G-3* compared to the G-4 and G-5 samples) can also greatly enhance the HER activity by reducing the ΔG H* close to zero as reported in the literature. [6,27] The activation energy of the Volmer step (discharge step) of the HER could be reduced significantly by assimilation of molybdenum with other metal atoms, subsequently enhancing the reaction kinetics. [6] It has been reported that the active sites on the electrode surface could be blocked by the hydroxides (OH À ) produced by the water dissociation in the Volmer reaction.…”

“…[6,27] The activation energy of the Volmer step (discharge step) of the HER could be reduced significantly by assimilation of molybdenum with other metal atoms, subsequently enhancing the reaction kinetics. [6] It has been reported that the active sites on the electrode surface could be blocked by the hydroxides (OH À ) produced by the water dissociation in the Volmer reaction. However, due to the strong electrostatic forces of attraction, the positively charged metal atoms (M n + , M = Co, Ni, and Mo) act as the water (hydroxide)-acceptor center.…”

“…This manifests that the kinetics of the G-3 sample is greatly accelerated, probably due to the integration of high valence Mo, which decreases the OÀ H bond strength, promotes the deprotonation process, and consequently increases the OER activity as reported in the literature. [6,27] Stability is another parameter to test the activity of a catalyst for practical applications. The G-3 sample's electrochemical stability was probed by long-term chronopotentiometry measurements at a relentless current density of 10 and 50 mA cm À 2 for 54 h (27 h for each).…”

“…The high activity of the G-3 sample can be ascribed to the following points. i) The nanoarrays structure originated by Modoping is beneficial to make an intimate contact between the active-sites and the electrolyte, lower the charge-transfer resistance and increase the mass and charge transport process during the electrocatalytic reaction; [6,27] ii) the NiCo 2 O 4 nanoparticles are well-dispersed on the surface of the CoMoO 4 nanosheet arrays, which provides multi-active sites, lowers the overpotential, and accelerates the reaction kinetics; iii) after Pdoping, the conjunction of P @À and M n + is favorable to trap the protons and hydroxides, respectively. [5b] Apart from that, the downshift of the Co 2p spectrum demonstrates the electronic structure of the sample is modified, which subsequently enhances the catalytic performance; iv) the unique structure of CMO-NAs along with the NF provides high structural stability to the catalyst while the space between the nanosheet arrays and the NF promotes the penetration of electrolyte and escape of gas molecules, thus promoting the catalytic activity at higher potentials.…”

Scaling Up the Production of Electrodeposited Nanowires: A Roadmap towards Applications

“…These nanoparticles are normally synthesized by chemical methods [ 5 ] that are easily scaled-up, enabling real world applications [ 6 ]. Nanowires (NWs), which are much less widespread in applications than nanoparticles, have emerged in recent years, as nanomaterials have been called upon to play an important role in the development of breakthrough technologies in many fields, such as novel computation and data recording schemes [ 7 , 8 ], neuroscience [ 9 , 10 ], drug delivery [ 11 , 12 ], chemical sensing [ 13 , 14 ] or water splitting [ 15 , 16 ] among others. Electrodeposition is a very suitable growth technique for the fabrication of these nanomaterials.…”