Japanese team designs a graphene-based electrode that can produce hydrogen under acidic conditions

Researchers at the Japanese Tsukuba University described a graphene-based electrode that can produce hydrogen under acidic conditions. The electrolysis of water to generate hydrogen is vital for energy storage in a green economy. One of the major obstacles, however, is the high cost of noble-metal electrodes. Cheaper non-noble electrodes function well in driving the hydrogen evolution reaction (HER), but mainly in alkaline conditions, where the reaction is electricity-hungry. The more efficient acid-phase reaction requires precious metals such as platinum. Worse still, the acid electrolytes are corrosive and eat away at the core metal.

Perforated graphene for hydrogen production image

The researchers have found that holey graphene offers a way around this problem. They used nitrogen-doped graphene sheets to encapsulate a nickel–molybdenum (NiMo) electrode alloy. The graphene was punched full of nanometer-size holes. The researchers showed that in acid conditions, their HER system dramatically outperforms an electrode using regular non-holey graphene. The use of graphene in HER electrodes is not new—this flexible, conductive carbon sheet is ideal for wrapping around the core metal. However, although it protects the metal against corrosion, graphene also suppresses its chemical activity. In the Tsukuba system, the holes promote the reaction in two ways, while the intact graphene part protects the metal.

University of Warsaw team develops a graphene-matrix with potential for medicine and food applications

Researchers at the Department of Chemistry of the University of Warsaw in Poland have developed a new graphene matrix, as a functional substrate for immobilizing enzymes, and the method of its preparation. The newly-patented graphene matrix may find applications in the food and medicine industries, like the production of biosensors and other electronic devices (eg. bands, tattoos).

A graphene matrix for applications in the food industry and medicine for the production of biosensors imageDiagram of a lactate biosensor composed of a graphene matrix and a lactate oxidase enzyme, deposited on a carbon electrode

The invention is used as a stable system with high sensitivity, not only in analytical biosensors, but also in bio-fuel cells used in medicine, biology and chemical biocatalysis. The solution concerns the enzymatic (protein) sensor construction for detection of lactates, which can be used in the food industry and medicine for the production of biosensors.

XFNano graphene materials used in advanced energy application research

The following is a sponsored post by XFNano

XFNano's graphene materials were recently used in two fascinating research work focused on advanced energy applications.

NiCo-HS@G fabrication (XFNano)

The first is a work by teams from Anhui Normal University, Chinese Academy of Sciences (CAS) and the University of the Chinese Academy of Sciences which developed a fast, one-step strategy to prepare sandwiched metal hydroxide/graphene composites through a kinetically controlled coprecipitation under room temperature. Such NiCo-HS@G nano-composite exhibits good electrocatalytic activity for OER, superior to most of the reported OER catalysts. Such performance and the facile preparation of NiCo-HS@G opens up a new avenue for the cost-effective and low-energy-consumption production of various sandwiched metal hydroxides/graphene composites as efficient OER electrocatalysts with desired morphology and competing performance for the applications in diverse energy devices.

Graphene sheets and nickel turn CO2 into usable energy

Researchers at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory are part of a scientific collaboration that has identified a new electrocatalyst that efficiently converts CO2 to carbon monoxide (CO), a highly energetic molecule.

“There are many ways to use CO,” says Eli Stavitski, a scientist at Brookhaven and an author on the paper. “You can react it with water to produce energy-rich hydrogen gas, or with hydrogen to produce useful chemicals, such as hydrocarbons or alcohols. If there were a sustainable, cost-efficient route to transform CO2 to CO, it would benefit society greatly”. Indeed, scientists have been looking for a way to do just that, but traditional electrocatalysts can't effectively initiate the reaction. That’s because a competing reaction, called the hydrogen evolution reaction (HER) or “water splitting,” takes precedence over the CO2 conversion reaction.

Rice University team detects metal in ‘metal-free’ graphene catalysts

Rice University scientists, led by Prof. James Tour, along with teams from the University of Texas at San Antonio and the Chinese Academy of Sciences, Beijing, China have detected a deception in graphene catalysts that, until now, gone unnoticed. Graphene has been widely tested as a replacement for expensive platinum in applications like fuel cells, where the material catalyzes the oxygen reduction reaction (ORR) essential to turn chemical energy into electrical energy.

Rice team finds  manganese atoms in graphene catalysts image

Since graphene isn't naturally metallic, researchers have been baffled by its catalytic activity when used as a cathode. The Rice team has now discovered that trace quantities of manganese contamination from graphite precursors or reactants hide in the graphene lattice. Under the right conditions, those metal bits activate the ORR. Tour said they also provide insight into how ultrathin catalysts like graphene can be improved.