Synthesis Of Efficient Ruthenium-based Alloy Catalysts And Their Catalytic Performance For Dehydrogenation Of Ammonia Borane

Hydrogen storage in an efficient,safe and cost-acceptable way is crucial for realizing the application of hydrogen energy.With the integration characteristics of production-storage-transportation,the hydrogen release from the hydrolysis of metal or hydride has become a hot topic in the field of hydrogen storage in recent years.Theoretically,hydrogen release amount of ammonia borane（NH₃BH₃,AB）hydrolysis system can reach 8.9 wt%.However,the sluggish kinetics of AB hydrolysis limits its practical application.Therefore,developing highly active and stable catalysts is the focus of AB catalytic hydrogen evolution.Herein,a series of Ru-based catalysts immobilized on graphene and MXenes（Ti₃C₂T_x）was successfully synthesized,and their catalytic performance for dehydrogenation from AB hydrolysis was systematically investigated.Meanwhile,the structure-performance relationship of the catalysts was also elucidated.The main research contents are as follows:（1）A series of graphene oxide-supported nitrogen-doped porous carbon-coated Ru-Co₂P catalytic materials（Ru-Co₂P@N-C/GO）was successfully synthesized via one-step phosphating method using Ru Co bimetallic MOFs as precursors.Benefiting from the doping of Ru affected the electronic structure of Co₂P,Ru-Co₂P@N-C/GO catalysts exhibit excellent catalytic performance for AB hydrolysis.The optimized Ru_0.01-Co₂P@N-C/GO exhibits a turnover frequency（TOF）and hydrogen generation rate（HGR）of 347.3 mol _H2·mol _Ru^–1·min^–1 and 83929 m L·min^–1·g _Ru^–1,respectively,at 298 K,with an activation energy（E_a）of 24.5 k J·mol^–1.Moreover,it maintains 84.1%of the original catalytic activity after 5 consecutive cycles.（2）A series of MXenes（Ti₃C₂T_x）supported Ru embedded in Co N/Co P composite catalysts（Ru-Co N/Co P@Ti₃C₂T_x）were successfully synthesized through a one-step phosphorization process using Ru Co-LDH nanosheets as precursors.The introduction of Ru with low content regulates the electronic environment of Co N/Co P heterostructure,resulting in superior catalytic activity for AB hydrolysis at 298 K.The TOF and HGR of Ru-Co N/Co P@Ti3C2Tx could reach up to 589.7 mol H₂·mol Ru^–1·min^–1 and 1.43×10⁵m L·min^–1·g _Ru^–1,respectively.Meanwhile,the E_a was as low as 26.3 k J·mol^–1.After 5hydrolysis reactions,it could still maintain 80%of the initial catalytic activity.（3）The reduced graphene oxide（r GO）anchored Ru-Ni bimetallic nanocluster catalysts（Ru Ni@PVP/r GO）were successfully synthesized through an in-situ reduction strategy using poly（N-vinyl-2-pyrrolidone）（PVP）as a surfactant.Since Ru-Ni nanoclusters are beneficial to the adsorption of H₂O and AB molecules,the activation of H₂O molecules in AB hydrolysis reaction is further promoted.The Ru₁Ni₁@PVP/r GO-1 catalyst exhibits a TOF and HGR of 425.1 mol _H2·mol _Ru^–1·min^–1 and 35836 m L·min^–1·g _Ru^–1,respectively,at298 K,with a much lower E_a of 21.1 k J·mol^–1.Moreover,Ru₁Ni₁@PVP/r GO-1 shows outstanding recyclability with 82.1%of the initial catalytic activity after 20 consecutive cycles,demonstrating excellent cycle stability.