The quest for sustainable energy sources has intensified the search for efficient ways to convert solar energy into chemical fuels. Photocatalytic hydrogen evolution, which splits water into hydrogen fuel using sunlight, is a promising technique. However, many photocatalysts suffer from low efficiency because the light-generated charges recombine too quickly instead of driving the chemical reaction. Covalent organic frameworks (COFs)—porous, crystalline materials with tunable structures—are excellent candidates for photocatalysis. Yet, their performance is often hampered by inefficient charge separation.
Herein, this study designed a solution by combining a specific COF, known as TpBD-COF, with uniquely shaped gold nanobipyramids (Au NBs). These gold nanostructures feature sharp tips that act as powerful nano-antennas, concentrating light energy into an intense local electric field. This amplified electric field enables the plasmon-mediated resonant energy transfer process. Essentially, the gold nanoparticles absorb light and efficiently transfer the energy to the surrounding COF, prompting it to generate more charge carriers needed for the hydrogen production reaction. The optimized hybrid material, containing 2% gold nanobipyramids, demonstrated a hydrogen evolution rate of 6.27 mmol·g^-1·h^-1, which is 3.5 times higher than that of the pure COF. Advanced spectroscopic analyses and simulations confirmed that the enhanced performance stems from the rapid and efficient energy transfer facilitated by the gold nanostructures, rather than from the direct injection of hot electrons.
This work entitled “Plasmonic Au nanobipyramid assembly covalent organic framework for boosting photocatalytic hydrogen evolution through strong local electric field” was published on Acta Physico-Chimica Sinica (published on September 23, 2025).

DOI: 10.1016/j.actphy.2025.100193