Kang Naixin, Wang Qi, Djeda Rodrigue, Wang Wenjuan, Fu Fangyu, Moro Marta Martinez, Ramirez Maria de Los Angeles, Moya Sergio, Coy Emerson, Salmon Lionel, Pozzo Jean-Luc, Astruc Didier
ISM, UMR CNRS N° 5255, Univ. Bordeaux, Talence Cedex 33405, France.
Soft Matter Nanotechnology Lab, CIC biomaGUNE, Paseo Miramón 182, Donostia-San Sebastián 20014, Gipuzkoa, Spain.
ACS Appl Mater Interfaces. 2020 Dec 2;12(48):53816-53826. doi: 10.1021/acsami.0c16247. Epub 2020 Nov 17.
Production of hydrogen (H) upon hydrolysis of inorganic hydrides potentially is a key step in green energy production. We find that visible-light irradiation of aqueous solutions of ammonia-borane (AB) or NaBH containing "click"-dendrimer-stabilized alloyed nanocatalysts composed of nanogold and another late transition-metal nanoparticle (LTMNP) highly enhances catalytic activity for H generation while also inducing alloy to Au core@M shell nanocatalyst restructuration. In terms of visible-light-induced acceleration of H production from both AB and NaBH, the AuRu alloy catalysts show the most significant light-boosting effect. Au-Rh and Au-PtNPs are also remarkable with total H release time from AB and NaBH down to 1.3 min at 25 °C (AuRh), 3 times less than in the dark, and Co is the best earth-abundant metal alloyed with nanogold. This boosting effect is explained by the transfer of plasmon-induced hot electron from the Au atoms to the LTMNP atoms facilitating water O-H oxidative addition on the LTMNP surface, as shown by the large primary kinetic isotope effect / upon using DO obtained for both AB and NaBH. The second simultaneous and progressive effect of visible-light irradiation during these reactions, alloy to Au core@M shell restructuration, enhances the catalytic activity in the recycling, because, in the resulting Au core@M shell, the surface metal (such as Ru) is much more active than the original Au-containing alloy surface in dark reactions. There is no light effect on the rate of hydrogen production for the recycled nanocatalyst because of the absence of Au on the NP surface, but it is still very efficient in hydrogen release during four cycles because of the initial light-induced restructuration, although it is slightly less efficient than the original nanoalloy in the presence of light. The dendritic triazole coordination on each LTMNP surface appears to play a key role in these remarkable light-induced processes.
无机氢化物水解产生氢气（H）可能是绿色能源生产中的关键步骤。我们发现，对含有由纳米金和另一种晚期过渡金属纳米颗粒（LTMNP）组成的“点击”树枝状聚合物稳定的合金纳米催化剂的氨硼烷（AB）或硼氢化钠（NaBH）水溶液进行可见光照射，可显著提高产氢的催化活性，同时还会诱导合金向金核@M壳纳米催化剂重构。就可见光诱导加速AB和NaBH产氢而言，金钌合金催化剂表现出最显著的光增强效应。金铑和金铂纳米颗粒也很显著，在25℃时，AB和NaBH的总氢释放时间降至1.3分钟（金铑），比黑暗中少3倍，钴是与纳米金合金化的最佳储量丰富的金属。这种增强效应可解释为等离激元诱导的热电子从金原子转移到LTMNP原子，促进了LTMNP表面水的O-H氧化加成，这在使用AB和NaBH的重水（DO）时获得的大的一级动力学同位素效应中得到体现。这些反应中可见光照射的第二个同时发生且逐步的效应，即合金向金核@M壳重构，增强了循环中的催化活性，因为在生成的金核@M壳中，表面金属（如钌）在黑暗反应中比原始含金银合金表面活性高得多。由于纳米颗粒表面没有金，循环使用的纳米催化剂的产氢速率没有光效应，但由于最初的光诱导重构，它在四个循环中仍能非常有效地释放氢气，尽管在有光的情况下它的效率略低于原始纳米合金。每个LTMNP表面的树枝状三唑配位似乎在这些显著的光诱导过程中起关键作用。
