CuS/RGO hybrid by one-pot hydrothermal method for efficient electrochemical sensing of hydrogen peroxide

In this study,a non-enzymatic hydrogen peroxide sensor was successfully fabricated on the basis of copper sulfide nanoparticles/reduced graphene oxide（CuS/RGO） electrocatalyst.Using thiourea as reducing agent and sulfur donor,CuS/RGO hybrid was synthesized through a facile one-pot hydrothermal method,where the reduction of GO and deposition of CuS nanoparticles on RGO occur simultaneously.The results confirmed that the CuS/RGO hybrid helps to prevent the aggregation of CuS nanoparticles.Electrochemical investigation showed that the as-prepared hydrogen peroxide sensor exhibited a low detection limit of 0.18μmol/L（S/N = 3）,a good reproducibility（relative standard deviation（RSD） of4.21%）,a wide linear range（from 3 to 1215 μmol/L） with a sensitivity of 216.9 μA L/mmol/cm-2 under the optimal conditions.Moreover,the as-prepared sensor also showed excellent selectivity and stability for hydrogen peroxide detection.The excellent performance of CuS/RGO hybrid,especially the lower detection limit than certain enzymes and noble metal nanomaterials ever reported,makes it a promising candidate for non-enzymatic H2O2 sensors.

Co_(1-x)S embedded in porous carbon derived from metal organic framework as a highly efficient electrocatalyst for oxygen evolution reaction

Developing active, robust, and cost-efficient electrocatalysts is critical for oxygen evolution reaction(OER). Here, a novel composite catalyst of Co_(1-x)S embedded in porous dodecahedron carbon hybrid was synthesized by a two-step conversion protocol of a cobalt-based metal-organic framework(ZIF-67). The porous dodecahedron Co_(1-x)S@C composite catalyst was prepared by direct oxidation of ZIF-67 followed by sulfurization reaction. The Co_(1-x)S@C composite exhibit superior OER performance, including a low overpotential of 260 mV for 10 mA/cm2, a small Tafel slope of ~85 mV/dec, outstanding stability over 80 h and almost 100% Faradaic efficiency. The various material characterizations indicate that the excellent activity and strong stability of Co_(1-x)S@C might be attributed to good conductivity of Co_(1-x)S, mesoporous nanostructure, and synergistic effect of Co_(1-x)S encapsulated within porous carbon. This work provides a novel strategy for designing and synthesizing advanced composite