Heterostructured Ni2Co Layered Double Hydroxide/Reduced Graphene Oxide Nanosheets for H2 Production Assisted by Benzylamine Oxidation

Hybrid water electrolyzers that use facile organic oxidation reactions (OOR) as an alternative to the sluggish oxygen evolution reaction (OER) are projected as high-value electrolyzers due to the simultaneous production of H-2 and value-added chemicals. In the present study, electro-oxidative dehydrogenation of benzylamine (BAm) to benzonitrile (BN) is carried out as an alternate oxidation reaction to OER, coupled with the hydrogen evolution reaction (HER), in a hybrid water electrolysis system. For this, heterostructures of Ni2Co layered double hydroxide (LDH) and reduced graphene oxide (rGO) are synthesized by using flocculation of oppositely surface-charged nanosheets and used for the benzylamine oxidation reaction (BAmOR). The Ni2Co-LDH/rGO heterostructures require 1.35 V vs RHE to achieve a current density of 10 mA cm(-2) in the presence of BAm, compared to 1.61 V vs RHE without BAm, indicating that BAmOR can be a potential alternate to OER. Upon utilizing Ni2Co-LDH/rGO heterostructures as the anode and commercial Pt as the cathode in a hybrid water splitting cell, faradaic efficiencies of similar to 94% and similar to 85% are achieved for H-2 and BN production, respectively. Additionally, the hybrid electrolysis cell is capable of producing 38.6 mu mol cm(-2) h(-1) H-2 even at a cell voltage of 1.39 V, whereas the traditional water electrolysis cell requires a cell voltage of 1.68 V to yield a similar (34.7 mu mol cm(-2) h(-1)) amount of H-2. This clearly suggests that substituting the OER with BAmOR is beneficial for not only achieving high efficiency in H-2 production but also producing value-added BN.