Using electrolysis of water to produce hydrogen, we can get clean hydrogen fuel, but high overpotential for oxygen evolution causes electrolysis of water to become more challenging. Ph.D. candidate Xueli Zheng from Institute of New Energy Materials, School of Materials Science and Engineering, during collaborative education in University of Toronto, designed high performance catalysts to achieve electrolysis of water with high efficiency. Research production was published in journal Science and she is the co-first author of the paper.

3d transition metal on element periodic table is abundant in the earth, whose relevant catalysts were widely used in water splitting reaction. However, only 3d transition metal regulation is not enough to satisfy the requirements of lowering the overpotential. The research team predicted that they can obtain the lowest overpotential of oxygen evolution to date by utilizing non-3d high-valency metals such as tungsten to modulate electronic structure of 3d metals iron and cobalt. (Figure 1)

Figure 1 Tuning the energetics of oxygen evolution reaction intermediates via alloying.

The research team developed a room-temperature synthesis to produce gelled amorphous FeCoW oxy-hydroxide catalysts with an atomically homogeneous metal distribution. Consistent with theory predicts, these gelled FeCoW oxy-hydroxide exhibited the lowest overpotential (191 mV) reported at 10 mA per square centimeter in alkaline electrolyte. The catalyst shows no evidence of degradation following more than 500 hours of operation. (Figure 2)

Cooperating with Canada Light Source and Beijing Synchrotron Radiation laboratory, they study systematically coordination environment and electronic structure of FeCoW oxy-hydroxide catalysts, which agreed well with the DFT prediction.

Figure 2 The testing of gelled FeCoW oxy-hydroxide catalysts in 1 M KOH aqueous
electrolyte. (A) Catalytic performance (B) Stability.

The study was highlighted by the experts in this field such as Prof. Jeffrey C. Grossman from MIT and Prof. Gabor A. Somorjai from UC Berkeley. At present, the work has been applied for international patent protection in Canada and reported at homepage of the relevant agencies such as SLAC National Accelerator Laboratory and University of Toronto. The research got financial support from China Scholarship Council and Canada Natural Science and Engineering Foundation, etc.

 Reference:

DOI: 10.1126/science. aaf1525

http://science.sciencemag.org/content/early/2016/03/23/science.aaf1525