Transition metal borides (TMBs) are known for their: low-cost, high activity, stability in both acidic and basic electrolytes in hydrogen evolution reaction (HER). Furthermore, nanoscale TMBs would have a larger surface area, thus showing an increased number of active sites, and leading to higher catalytic performance. This was proven in a recent study where TMB nanoparticles, synthesized by Sn flux, showed significantly higher catalytic activity than their bulk counterparts, despite their high aggregation. It remains a challenge to synthesize highly dispersed TMB nanoparticles.
In this study, the effect of excess Sn in TMB nanosynthesis is analyzed. Excessive flux in the synthesis is correlated to an increased reaction rate, thus enabling milder reaction conditions, such as lower temperature and shorter reaction time. With the experimental modifications of Sn amount and reaction conditions, its effects on the size, aggregation, and HER catalytic activity of the produced TMB nanoparticles were studied.