The transition metal doped B cluster (TM4B18) as catalysis for nitrogen fixation

•Through comprehensive genetic algorithm (CGA) method, 18 kinds of transition metal boron cluster TM4B18 (TM = 3d, 4d and 5d) are explored.•The photocatalytic NRR potential of these clusters are thoroughly discussed for the first time.•Based on a “Four-Step” strategy, three promising candidates including Mn4B18, V4B18 and Zr4B18 with great performance are extracted out from 18 catalysts.