Strong　metal–support　interaction　(SMSI)　is　a　phenomenon　commonly　observed　on　heterogeneous　catalysts.　Here,　direct　evidence　of　SMSI　between　noble　metal　and　2D　TiB2　supports　is　reported.　The　temperature-induced　TiB2　overlayers　encapsulate　the　metal　nanoparticles,　resulting　in　core–shell　nanostructures　that　are　sintering-resistant　with　metal　loadings　as　high　as　12.0　wt%.　The　TiOx-terminated　TiB2　surfaces　are　the　active　sites　catalyzing　the　dehydrogenation　of　formic　acid　at　room　temperature.　In　contrast　to　the　trade-off　between　stability　and　activity　in　conventional　SMSI,　TiB2-based　SMSI　promotes　catalytic　activity　and　stability　simultaneously.　By　optimizing　the　thickness　and　coverage　of　the　overlayer,　the　Pt/TiB2　catalyst　displays　an　outstanding　hydrogen　productivity　of　13.8 mmol　g−1cat　h−1　in　10.0　m　aqueous　solution　without　any　additive　or　pH　adjustment,　with　＞99.9% selectivity　toward　CO2　and　H2.　Theoretical　studies　suggest　that　the　TiB2　overlayers　are　stabilized　on　different　transition　metals　through　an　interplay　between　covalent　and　electrostatic　interactions.　Furthermore,　the　computationally　determined　trends　in　metal–TiB2　interactions　are　fully　consistent　with　the　experimental　observations　regarding　the　extent　of　SMSI　on　different　transition　metals.　The　present　research　introduces　a　new　means　to　create　thermally　stable　and　catalytically　active　metal/support　interfaces　for　scalable　chemical　and　energy　applications.　©　2021　Wiley-VCH　GmbH