Palladium Gold Alloy Nanoparticles Loaded On Aminated MIL-101 For Hydrogen Production From Formic Acid Decomposition

To meet the growing energy challenge,hydrogen（H₂）has emerged as an environmentally friendly clean fuel and a promising energy carrier.The safe and efficient storage/release of H₂ is the bottleneck to the future economy of hydrogen.Formic acid（FA）is a promising liquid carrier for storage of H₂ and there is an urgent need to exploitation and fabrication heterogeneous catalysts with excellent catalytic activity for the production of H₂ from the decomposition of FA under mild conditions in practical applications,but this remains a considerable challenge.Therefore,in this thesis,we designed and synthesized a series of Pd Au nanocatalysts loaded on aminated MIL-101 for highly active and selective production of H₂ from the decomposition of FA.The main studies are as follows:We prepared the supporter NH₂-MIL-101 with higher yield by adding Na OH to assist in the synthesis of NH₂-MIL-101.Pd_0.7Au_0.3/NH₂-MIL-101 nanocatalyst was successfully synthesized by a simple surfactant-free co-reduction strategy,which has good catalytic activity for the FA dehydrogenation reaction.Based on the results of a series of characterization tests and performance tests,it is known that:the prepared Pd_0.7Au_0.3/NH₂-MIL-101 nanocatalyst with ultrafine alloy particles（average particle size of 0.81±0.22 nm）,good dispersibility and abundant active sites.The optimized Pd_0.7Au_0.3/NH₂-MIL-101 nanocatalyst has good catalytic activity(turnover frequency（TOF）=2921.0 h^–1),about 100%H₂ selectivity and FA conversion for H₂ production from FA decomposition at 323 K without additives.It showed better catalytic activity for H₂ production from FA decomposition in the presence of sodium formate（SF）at323 K(TOF=4718.6 h^–1 at n _SF/n _FA=3).The catalytic performance of Pd_0.7Au_0.3/NH₂-MIL-101 nanocatalyst is comparable to the best MOF-based FA dehydrogenation heterogeneous catalysts that have been reported so far.To further increase the catalytic activity of the catalyst,NH₂-MIL-101 was modified by 3-aminopropyltriethoxysilane（APTES）for the amino functionalization of NH₂-MIL-101,resulting in DA-MIL-101（DA=diamino,double amino）;The Pd_0.7Au_0.3/DA-MIL-101 nanocatalyst was successfully synthesized by a one-step co-reduction method,which has excellent catalytic activity for FA dehydrogenation reaction.Based on the results of a series of characterization tests and performance tests,it is known that:The prepared Pd_0.7Au_0.3/DA-MIL-101 nanocatalyst has fine alloy particles（average particle size is 1.90±0.41 nm）,good dispersion and rich active sites.The optimized Pd_0.7Au_0.3/DA-MIL-101 nanocatalyst has excellent catalytic activity(TOF=6457.0 h^–1),about 100%H₂ selectivity and FA conversion for H₂ production from FA decomposition at 323 K without additives.It showed better catalytic activity for H₂ production from FA decomposition in the presence of SF at 323 K(TOF=8763.1h^–1 at n _SF/n _FA=3).