Electrolytic hydrogen production powered by renewable energy is seen as an environmentally friendly means to ameliorate global climate and energy problems. In the journal Angewandte Chemie, a research team has now introduced a novel and inexpensive material for electrodes that may provide for highly efficient, energy-saving hydrogen production: porous, phosphorized CoNi2S4 yolk-shell nanospheres.

Both half reactions of water electrolysis-hydrogen and oxygen evolution-are unfortunately slow and require a lot of power. Catalytically effective electrodes, particularly those based on precious metals, can accelerate the electrochemical processes and improve their energy efficiency. However, their large-scale use is impeded by high costs, limited abundance, and low stability. Alternatives based on abundant, inexpensive metals usually do not work satisfactorily for both half reactions.

A team led by Shuyan Gao (Henan Normal University, China) and Xiong Wen (David) Lou (Nanyang Technological University, Singapore) has now developed a novel, inexpensive, multifunctional electrode material based on cobalt (Co) and nickel (Ni) for efficient electrocatalytic hydrogen production.

To make the material, nanospheres made of cobalt-nickel-glycerate are subjected to combined hydrothermal sulfidation and gas-phase phosphorization. This forms objects called yolk-shell nanoparticles made of phosphorus-doped cobalt-nickel-sulfide (P-CoNi2S4). These are tiny spheres with a compact core and a porous shell with a space in between-much like an egg whose yolk is surrounded by the egg white and so does not touch the shell.

Phosphorus doping increases the proportion of Ni3+ relative to Ni2+ in the hollow particles and allows for faster charge transfer, causing the electrocatalytic reactions to run faster. The material can be used as either an anode or a cathode, and demonstrates high activity and stability in the production of hydrogen and oxygen in the electrolysis of water.

To reduce the overall voltage of the electrolysis cell, hybrid electrolysis concepts are also being researched. For example, instead of being coupled to the production of oxygen, hydrogen production could be coupled to the oxidation of urea, which requires significantly less energy. Sources of urea could include waste streams from industrial syntheses as well as sanitary sewage. The new nanoparticles are also very useful for this half reaction.

Both water and urea electrolysis require comparatively low cell voltage (1.544 V or 1.402 V, respectively, at 10 mA cm-2 over 100 hours). This makes the new bimetallic yolk-shell particles superior to most known nickel-sulfide- and even precious-metal-based electrocatalysts. They present a promising approach for electrochemical hydrogen production, as well as for the treatment of urea-containing wastewater.

Research Report: "Phosphorized CoNi2S4 Yolk-Shell Spheres for Highly Efficient Hydrogen Production via Water and Urea Electrolysis"

Related Links
Henan Normal University
All About Oil and Gas News at OilGasDaily.com

Tweet

Thanks for being here; We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain. With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords. Our news coverage takes time and effort to publish 365 days a year. If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor $5 Billed Once credit card or paypal		SpaceDaily Monthly Supporter $5 Billed Monthly paypal only

Iraqi PM to discuss energy, Saudi ties with Iran's president
Baghdad (AFP) Sept 10, 2021
Iraqi Prime Minister Mustafa al-Kadhemi will meet Iran's president on Sunday in Tehran to discuss issues including energy and Iran-Saudi relations, a government source said Friday. The visit will mark Kadhemi's first meeting with Ebrahim Raisi since the ultra-conservative president took office last month, and comes ahead of Iraq's October 10 legislative polls. Kadhemi will raise "issues of security, energy, and relations between Saudi Arabia and Iran" with Raisi, a government source said, reques ... read more