Porous Nickel Electrodes with Controlled Texture for Hydrogen Evolution Reaction and Sodium Borohydride Electrooxidation

Porous Ni electrodes with different texture are fabricated by a facile electro-deposition method. The additives of ammonium chloride (NH4Cl) or ammonium sulfate ((NH4)2SO4) in supporting electrolytes play a vital role in the texture of porous electrodes. Porous Ni electrodes prepared from NH4Cl additive presents a (111) plane preferred orientation. However, for the additive of (NH4)2SO4, as its concentration increases, the preferred orientation is changed from (111) to (200) plane. In addition, we studied about the texture of porous Ni electrodes and their influence on Hydrogen Evolution Reaction (HER) and sodium borohydride (NaBH4) electrooxidation. Porous Ni electrodes with (111) preferential orientation are conducive to promoting the electrooxidation of NaBH4. Meanwhile, the optimum catalytic activity can be obtained when both the (111) and (220) are preferentially oriented. In contrast, porous Ni electrodes with (200) preferential orientation facilitate NaBH4 hydrolysis. Interestingly, the porous Ni electrode with both (200) and (220) preferential orientation exhibits the best HER catalytic activity. This work provides new insight into the relationship between the texture and electrocatalytic properties of porous Ni electrodes, which is desirable to design nickel electrodes more reasonably for HER or sodium borohydride electrooxidation.