Ni/Ni3S2 catalyst for alkaline HER. TEM images showed a highly disorganized structure where the lattice constant could not be identified. Our calculations demonstrated poor results for the pure close-packed phases of both Ni and Ni3S2 with superior reactivity at the interface. (These results were later supplemented with GCDFT calculations on both pure surfaces, shown in Figure .) We initially constructed an interface of 2 pristine phases to model the interface, but this may not reflect the complexity of the real surface. For this reason, we performed further simulated annealing on our original interface structure from Li. To mimic the conditions of synthesis, we first increased the temperature of the systems by 1K/fs for 1 ps using a micro-canonical ensemble. The structure was then kept at 1000K for 10 ps under an NVT ensemble. Finally, a micro-canonical ensemble brought the temperature down by 1K/fs for another 1 ps.