Thiomolybdate [Mo3S13]2– nanoclusters anchored on reduced graphene oxide-carbon nanotube (rGO-CNTs) aerogels were used as a new catalyst for efficient electrocatalytic hydrogen evolution. The elemental distribution of sulfur (S) corresponded well to the Mo distribution, and both Mo and S elements distributed evenly in the Mo3S13@rGO-CNTs aerogels. Results indicated that [Mo3S13]2– nanoclusters inherently exposed a high number of active edge sites, which greatly improved the electrocatalytic hydrogen evolution. The new peak at 168.8 eV corresponded to the characteristic S–O binding in the S 2p region of Mo3S13@rGO-CNTs, indicating that the [Mo3S13]2– clusters were bond onto the rGO-CNTs aerogels through S–O binding. The strong support of rGO-CNTs aerogels suppressed the aggregation of [Mo3S13]2– nanoclusters, exposing more active surface and electrons diffusions on the surface of Mo3S13@rGO-CNTs aerogels. Mo3S13@rGO-CNTs aerogels laden with 20 mg of [Mo3S13]2– exhibited close hydrogen evolution reaction (H...