Guanghui Zhang

L-cysteine, a component of the symmetric L-cystine, is essential in numerous biological activities. Thus, detecting cysteine rapidly, selectively, and sensitively is of tremendous interest. Herein, g-C₃N₄@CdS composites were employed as sensing elements in a photoelectrochemical platform for L-cysteine sensing. In this system, g-C₃N₄@CdS composites provided much better optoelectronic function than bare CdS materials owing to their high photon-to-current conversion efficiency and excellent anti-photocorrosion properties. The innovative photoelectrochemical sensor has a wide determination range of 5 to 190 µM, a very low detection limit of 1.56 µM, a fast response time, and good long-term stability (ca. 1 month). Without applying any separation procedures, a low concentration of CySH was successfully detected in human urine samples, which is compatible with the results of chemiluminescence.

Developing earth-abundant electrocatalysts useful for hydrogen evolution reactions (HER) is critical for electrocatalytic water splitting driven by renewable energy. Molybdenum carbide (Mo₂C) with the crystal structure of hexagonal symmetry has been identified to be an excellent HER catalyst due to its platinum-like electronic structure while the synthesis of Mo₂C is generally time consuming and energy intensive. Herein, we demonstrated the ultrafast synthesis of a Mo₂C-based electrocatalyst with Joule heating at 1473 K for only 6 s. Benefitting from several advantages including efficient catalytic kinetics, enhanced charge transport kinetics and high intrinsic activity, the as-prepared catalyst exhibited drastically enhanced HER performance compared with commercial Mo₂C. It showed an overpotential of 288 mV for achieving a current density of −50 mA cm⁻² and good stability, which highlighted the feasibility of the Joule heating method towards preparing efficient electrocatalysts.