No abstract

A notable trend in OER activity on transition metal phosphide pre-catalysts is reported. Remarkably, the tri-metallic FeCoNiP pre-catalysts exhibit exceptional apparent and intrinsic OER activities, outperforming many non-precious OER catalysts reported previously.

A microporous-mesoporous carbon with graphitic structure was developed as a matrix for the sulfur cathode of a Li-S cell using a mixed carbonate electrolyte. Sulfur was selectively introduced into the carbon micropores by a melt adsorption-solvent extraction strategy. The micropores act as solvent-restricted reactors for sulfur lithiation that promise long cycle stability. The mesopores remain unfilled and provide an ion migration pathway, while the graphitic structure contributes significantly to low-resistance electron transfer. The selective distribution of sulfur in micropores was characterized by X-ray photoelectron spectroscopy (XPS), nitrogen cryosorption analysis, transmission electron microscopy (TEM), X-ray powder diffraction and Raman spectroscopy. The high-rate stable lithiation-delithiation of the carbon-sulfur cathode was evaluated using galvanostatic charge-discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. The cathode is able to operate reversibly over 800 cycles with a 1.8 C discharge-recharge rate. This integration of a micropore reactor, a mesopore ion reservoir, and a graphitic electron conductor represents a generalized strategy to be adopted in research on advanced sulfur cathodes.

Wu et al. demonstrate that a >95% H 2 O 2 selectivity can simply be achieved in an electrosynthesis by using a positively charged surfactant on metal-free carbon electrode without needing sophisticated material design. Under the oxygen reduction reaction, the positively charged promoter pulls off adsorbed peroxide as formed, promoting the release of peroxide while protecting carbon surface from corrosion. It works well with surface carboxylates with weak binding, whereas carbonyl groups hold on to peroxides strongly and thus hinder the desorption and release.