Effects of B Addition on Microstructure Evolution and Efficient Hydrogen Evolution of Self‐Supported Cu–Fe–P Immiscible Alloy

Herein, the effect of B elements on the microstructure and catalytic properties of Cu–31.5Fe–4.5P immiscible alloy is systematically investigated. After microstructure characterizations, it is found that B elements are mainly concentrated in Fe x P (Fe 2 P, Fe 3 P) particles, which affect the Marangoni motion of the particles. With the concentration of B content increasing to 0.75%, the diameter size of the second‐phase particles in the alloys is first refined and then coarsened, in which the alloy with B content of 0.25% has the finest particle size and the proportion of second‐phase particles with sizes ranging from 1 to 10 μm reaches 97%. The electrochemical characterization of dealloyed specimens shows that the overpotential of Cu–Fe–P alloys containing 0.25% B reaches 193 mV at a current density of 10 mA cm −2 in 0.5 m H 2 SO 4 solution. The excellent catalytic performance might be attributed to the increase in the obviously specific surface area of Fe 2 P and Fe 3 P particles and the significant increase in the electron transfer.