Low-cost Oxygen Evolution Reaction Research Articles

In situ growth of NiTe nanosheet film on nickel foam as electrocatalyst for oxygen evolution reaction

Developing effective and low-cost oxygen evolution reaction (OER) electrocatalysts based on earth-abundant elements is vital for future clean and regenerated energy systems. In this work, one-step growth of NiTe nanosheet film on nickel foam (NiTe/NF) via a facile tellurization treatment of NF has been demonstrated. This NiTe/NF electrode exhibits remarkable OER activity with overpotential requirement as low as 262 mV to deliver an anodic current density of 10 mA cm−2, as well as superior durability in alkaline solution. This work provides an attractive earth-abundant 3D catalyst electrode for OER in overall water splitting.

NiFe Oxide Nanocatalysts Grown on Carbonized Algal Cells for Enhanced Oxygen Evolution Reaction

Carbon nanostructures are known to serve as a scaffold for growth of efficient water-splitting nanocatalysts. Here we have used Tetraselmis algal cells as both a renewable and sustainable carbon source and a biotemplate to synthesize low-cost oxygen evolution reaction (OER) NiFe oxide nanocatalysts. The nanocatalysts were grown on Tetraselmis-derived carbonized cells (cCells), a three-dimensional (3D) carbon scaffold, by two approaches. In the first approach, the catalyst components were loaded on cells prior to carbonization (pre-loading method). The nanocatalysts were then grown by using silica precursor tetramethoxysilane to generate NiFe(OH)x@Cell-SiO2 composites. Further pyrolysis produced NiFe oxides on electrically conductive cCells (NiFeOx@cCell). The cCells were reduced graphene oxide with 3D morphology. In the second approach, the cCells were synthesized first, followed by a hydrothermal reaction with the catalyst precursors (post-loading method). In comparison with the pre-loading method, the post-loading method enabled to load more nanocatalysts on individual cCells, which were highly efficient, with OER performance superior to that of the benchmark OER catalyst Ir/C. Our current methods may offer a new opportunity for using microalgae-derived, highly efficient water-splitting nanocatalysts for hydrogen production.

3D nickel-cobalt diselenide nanonetwork for highly efficient oxygen evolution

Active, stable and low-cost oxygen evolution reaction (OER) catalyst for electrochemical water splitting is key to efficient energy conversion and storage. Here, we report a three-dimensional (3D) nanonetwork as noble-metal-free electrode consisting of nickel cobalt diselenide (NiCoSe2) nanobrush arrays on Ni foam (NF) through the initial hydrothermal reaction and subsequent thermal selenization process. Introducing ammonium fluoride as surface controller, different NiCoSe2 hierarchical architecture can be modulated from nanorods, nanobrush to nanosheets. The unique brush-like NiCoSe2 possesses high surface area for mass transfer, rough surface with rich active sites, 3D nanostructure preventing the accumulation of O2 bubbles. Compared to NiCoSe2 nanorods/NF, NiCoSe2 nanosheets/NF and commercial RuO2, NiCoSe2 nanobrush/NF exhibits an enhanced OER performance in alkaline media to reach a low overpotential of 274mV at the current density of 10mA/cm2, small Tafel slope and a long-term stability. The developed 3D nanonetwork highlights the nanoscale engineering and offers a promising alternative to noble metal catalysts for electrochemical water oxidation.

A mini review on nickel-based electrocatalysts for alkaline hydrogen evolution reaction

High gravimetric energy density, earth-abundance, and environmental friendliness of hydrogen sources have inspired the utilization of hydrogen fuel as a clean alternative to fossil fuels. Hydrogen evolution reaction (HER), a half reaction of water splitting, is crucial to the low-cost production of pure H2 fuels but necessitates the use of electrocatalysts to expedite reaction kinetics. Owing to the availability of low-cost oxygen evolution reaction (OER) catalysts for the counter electrode in alkaline media and the lack of low-cost OER catalysts in acidic media, researchers have focused on developing HER catalysts in alkaline media with high activity and stability. Nickel is well-known as an HER catalyst and continuous efforts have been undertaken to improve Ni-based catalysts as alkaline electrolyzers. In this review, we summarize earlier studies of HER activity and mechanism on Ni surfaces, along with recent progress in the optimization of the Ni-based catalysts using various modern techniques. Recently developed Ni-based HER catalysts are categorized according to their chemical nature, and the advantages as well as limitations of each category are discussed. Among all Ni-based catalysts, Ni-based alloys and Ni-based hetero-structure exhibit the most promising electrocatalytic activity and stability owing to the fine-tuning of their surface adsorption properties via a synergistic nearby element or domain. Finally, selected applications of the developed Ni-based HER catalysts are highlighted, such as water splitting, the chloralkali process, and microbial electrolysis cell.