From a heterogeneous catalyst perspective, HEB are refractory borides that are insoluble in solution which enables their recovery and reuse. From a homogeneous catalyst perspective, HEB is comprised of borophene sheets that sandwich metals. In effect, the borophene layers serve as a shielding ligand and the edges of single crystals would thus resemble a metallocene. This heterogeneous catalyst comprised of significant extended covalent structures that would provide the protective effect of ligands in homogeneous catalysts while maintaining the recoverability and industrial relevance of heterogeneous catalysts. Here, the covalent network would isolate catalytically active metal centers just like homogeneous catalysts, and the exposed surface of the single crystal facets would perform like anchored homogeneous catalysts but with exceptionally higher stability owing to the refractory nature of heterogeneous catalysts.