Heterostructured B-C particles: Bridging solid and mesoporous domains

Microparticles comprising two macroscopically distinct domains with different compositions, structures, and porosity are attractive as multifunctional materials. B–C microparticles with dual-domain structures were synthesized via single-pulse laser heating of graphite–boron mixtures on chemical vapor deposition diamond. Vapor condensation forms Cassie–Baxter droplets featuring two distinct regions: a near-contact, mesoporous rapidly quenched (RQ) boron-doped onion-like carbon (OLC) network (∼4.7 at. % B) and a dense, quasi-equilibrium (QE) hypereutectic C–B4.5C mixture. Molecular dynamics simulations support the RQ structure. The results demonstrate that local supercooling suppresses boron diffusion, enabling the coexistence of mesoporous and dense domains within a single heterostructured microparticle.