Highly Durable Platinum Catalysts on Nano-SiC Supports with an Epitaxial Graphene Nanosheet Layer Grown from Coffee Grounds for Proton Exchange Membrane Fuel Cells

Robust ceramic supports have attracted significant attention as alternatives to carbon supports for proton exchange membrane fuel cells (PEMFCs). However, they suffer from lower electrocatalytic activities than carbon-based supports because of their electrical conductivity. Here, SiC nanopowders were modified with epitaxial graphene and evaluated as the support for Pt in PEMFCs. Coffee grounds are used as a carbon source to not only enhance the electrocatalytic activity of the graphene-modified SiC supports but also demonstrate the feasibility of exploiting and commercializing this widely available waste product. The Pt-decorated ceramic supports deliver the enhanced durability and performance under the accelerated electro′chemical conditions

High-Performance Electrochemical and Photoelectrochemical Water Splitting at Neutral pH by Ir Nanocluster-Anchored CoFe-Layered Double Hydroxide Nanosheets

Highly efficient electrocatalysts for the oxygen evolution reaction (OER) in neutral electrolytes are indispensable for practical electrochemical and photoelectrochemical water splitting technologies. However, there is a lack of good, neutral OER electrocatalysts because of the poor stability when H+ accumulates during the OER and slow OER kinetics at neutral pH. Herein, we report Ir species nanocluster-anchored, Co/Fe-layered double hydroxide (LDH) nanostructures in which the crystalline nature of LDH-restrained corrosion associated with H+ and the Ir species dramatically enhanced the OEC kinetics at neutral pH. The optimized OER electrocatalyst demonstrated a low overpotential of 323 mV (at 10 mA cm–2) and a record low Tafel slope of 42.8 mV dec–1. When it was integrated with an organic semiconductor-based photoanode, we obtained a photocurrent density of 15.2 mA cm–2 at 1.23 V versus reversible hydrogen in neutral electrolyte, which is the highest among all reported photoanodes to our knowledge