The　sluggish　water　dissociation　(Volmer　step)　is　a　rate-limiting　step　slowing　down　alkaline　hydrogen　evolution　reaction　(HER),　and　therefore　hinders　the　efficient　industrial　production　of　clean　hydrogen　resource.　In　this　work,　we　report　that　the　Volmer　step　can　be　facilitated　by　in-situ　surface　reconstruction　on　a　composite　between　cobalt　carbonate　hydroxide　and　titanium　oxide　(TiO2@CoCH),　and　the　resultant　activated　structure　turns　to　be　a　highly　efficient　electrocatalyst　for　alkaline　HER.　Experimental　characterization　and　density　functional　theory　calculation　evidence　that　under　HER　potential　the　smooth　TiO2@CoCH　surface　is　roughened　and　Co　interstitial　defects　in　TiO2　are　formed,　which　are　energetically　favorable　for　Volmer　step.　The　activated　composite　exhibits　an　overpotential　of　99　?　6　mV　for　a　current　density　of　20　mA　cm-2　and　187　?　21　mV　for　100　mA　cm-2,　suggesting　that　TiO2@CoCH　is　one　of　promising　non-precious　metal　electrocatalysts　for　HER　in　alkaline　media.