Metal-free 2D-2D black phosphorus/covalent organic framework p-n heterojunction for efficient visible-light-driven hydrogen evolution without cocatalysts

Abstract

Covalent organic frameworks (COFs), as a brand-new classification of propitious photocatalysts, which have caused serious concern due to its possible utilization in the changeover of resources into “solar fuels”, is challenged by low efficiency of charge separation. Herein, a metal-free 2D-2D BP/TpPa-1-COF p-n hetero-junction was compounded by an effortless solvothermal approach. The construction of BP/TpPa-1-COF p-n hetero-junction could effectively solve the problem of high recombination rate of photoelectron-hole pairs. Optimal sample (15% BP/TpPa-1-COF) exhibited the highest hydrogen production (456.7 μmol·h−1·g−1) among all heterostructures with non-noble loading, which has been raised 13 times compared with that of pristine TpPa-1-COF and 24 times of 2D BP flakes, respectively. This work not only improved the catalytic efficiency by accelerating the detachment and transport of charge carriers among different interfaces, but also indicated an effective method for constructing highly-efficiency metal-free and cocatalysts-free COF-based photocatalysts.