Nanostructured Molybdenum Oxides from Aluminium-Based Intermetallic Compound: Synthesis and Application in Hydrogen Evolution Reaction

Abstract

Characterized by a large surface area to volume ratio, nanostructured metal oxides possess unique chemical and physical properties with applications in electronics, catalysis, sensors, etc. In this study, Mo3Al8, an intermetallic compound, has been used as a precursor to obtain nanostructured molybdenum oxides. It was prepared into ribbons by arc-melting and melt-spinning techniques. Single and double-step free corrosion of the as-quenched material have been studied in 1 M KOH, 1 M HF and 1.25 M FeCl3 at room temperature. In both cases, nanostructured molybdenum oxides were obtained on a surface layer a few microns thick. Two of the as-prepared samples were tested for their electrocatalytic capability for hydrogen evolution reaction (HER) in 0.5 M H2SO4 giving low onset potential (−50 mV, −45 mV), small Tafel slopes (92 mV dec−1, 9 mV dec−1) and high exchange current densities (0.08 mA cm−2, 0.35 mA cm−2 respectively). The proposed nanostructured molybdenum oxides are cost-effective and sustainable due to the cheap and abundant starting material used and the simple synthetic route, paving the way for their possible application as HER electrocatalysts.

Composite MAX phase/MXene/Ni electrodes with a porous 3D structure for hydrogen evolution and energy storage application

“…Optimization ) during etching of the Mo 3 Al 8 phase in 1 M KOH solution. 57,58 Therefore, the Al etching of Mo 2 TiC 2 Al and, possibly also partial Mo dissolution is responsible for the formation of free space between the Mo 2 -TiC 2 (OH) x MXene layers and the observed appearance of a small-angle peak in the range 7-8.5°. In addition, several new unidentied new peaks in the XRD pattern of the Mo5Na sample were observed at 30.3°and 44.4°.…”

Cobalt–Iron–Phosphate Hydrogen Evolution Reaction Electrocatalyst for Solar-Driven Alkaline Seawater Electrolyzer

“…Electrochemical impedance spectroscopy (EIS) was performed at an overpotential of −0.25 V RHE for HER in the frequency range from 100 kHz to 0.01 Hz with an amplitude of 10 mV. The double-layer capacitance (C dl ) was estimated in the 1 M KOH solution via cyclic voltammetry (CV) at different scan rates (10,20,40,80, and 160 mV/s) in the non-faradaic region. The durability tests for HER were performed at a constant current density of −100 mA/cm 2 for 72 h. The Faradaic efficiency (FE) was determined via the water displacement method.…”

“…Therefore, numerous studies have been conducted to overcome this and explore non-precious-metal alternatives. So far, many transition-metal-based catalysts, i.e., oxides [18][19][20], hydroxides [21][22][23], sulfides [24][25][26], nitride [27][28][29], selenides [30,31], boride [32,33], chalcogenide [34,35], and phosphides/phosphate [36][37][38][39], have been developed. Among them, transition metal phosphate/phosphide (TMP) showed most effective catalytic activity for HER [40][41][42][43][44].…”

Breaking Down SERS Detection Limit: Engineering of a Nanoporous Platform for High Sensing and Technology

“…In particular, nanoporous metals prepared by dealloying techniques have been receiving research interest and exhibit promising results in several fields of application: actuators [ 1 ], storage and conversion of energy [ 2 ], electrodes for electrocatalysis [ 3 , 4 ], electrochemical biosensors [ 5 , 6 , 7 ], and surface-enhanced Raman scattering [ 8 , 9 ]. Scattering enhancement has been ascribed to their high surface area and their morphology constituted in ligaments, ranging from tens to hundreds of nanometers, and basically composed of the noblest elements of the original alloy.…”