Scalable synthesis of graphene-wrapped CoSe2-SnSe2 hollow nanoboxes as a highly efficient and stable electrocatalyst for hydrogen evolution reaction

For the first time, a novel electrocatalyst constructed by reduced graphene oxide (RGO)-wrapped CoSe2SnSe2 hollow nanoboxes (RCSB) has been synthesized by aqueous reaction, spray drying and selenization, which is facile, low-cost and easy to realize scalable production. Compared to bare CoSe2-SnSe2 nanoboxes (CSB), RCSB exhibits better electrocatalytic behavior for hydrogen evolution reaction (HER): the HER mechanism of RCSB is improved from Volmer-Heyrovsky combination (CSB) to Volmer-Tafel combination; the Tafel slope of RSCB dramatically decreases from 70.3 mV dec(-1) (CSB) down to 36.7 mV dec(-1), which nearly approaches to that of commercial Pt/C catalyst; RCSB delivers a very large current density of 36.7 mA cm(-2) at 250 mV, which is over 60 times larger than that of CSB (0.6 mA cm(-2)); moreover, RCSB shows excellent electrocatalytic stability even after 1500 cycles. The superior HER performance of RCSB can be attributed to the unique conductive hollow nanobox structure, which can not only guarantee interconnected conductive paths in the whole electrode, but also provide abundant catalytic active sites and facilitate the charge transportation between the electrocatalyst and electrolyte. This work provides insight into rational design and low-cost synthesis of non-precious transition-metal chalcogenide-based electrocatalysts with high efficiency and excellent stability for HER. (C) 2017 Elsevier Ltd. All rights reserved.