Engineering morphologies of yttrium oxide supported nickel catalysts for hydrogen production

The catalytic performance is highly related to the catalyst structure.Herein,a series of Ni nanoparticles supported on Y_(2)O_(3) with different morphologies were successfully synthesized via hydrothermal process screening different pH environments.These Ni/Y_(2)O_(3)catalysts were applied to efficiently produce CO_(x)-free H2through ammonia decomposition.We identify a significant impact of Y_(2)O_(3)supports on nickel nanoclusters sizes and dispersion.The experimental results show that Ni/Y11 catalyst achieves 100% ammonia decomposition conversion under a gas hour space velocity(GHSV) of 12,000 ml·h^(-1)·gcat^(-1) and temperature of 650℃.Such a high level of activity over Ni/Y11 catalyst was attributed to a large specific surface area,appropriate alkalinity,and small Ni nanoparticles diameter with high dispersion.

Y_(2)O_(3)-functionalized graphene-immobilized Ni–Pt nanoparticles for enhanced hydrous hydrazine and hydrazine borane dehydrogenation

Developing efficient and highly selective catalyst to promote hydrogen generation from hydrous hydrazine(N_(2)H_(4)·H_(2)O) and hydrazine borane(N_(2)H_(4)BH_(3))remains a challenging issue for fuel cell-based hydrogen economy.In this work,ultrafine and well-dispersed bimetallic NiPt nanoparticles(3.4 nm) were successfully immobilized on Y_(2)O_(3)-functionalized graphene(Y_(2)O_(3)/rGO) without any surfactant by a simple liquid impregnation approach.It is firstly found that integration of graphene and Y_(2)O_(3) not only can facilitate the formation of ultrafine NiPt nanoparticles(NPs),but also can effectively modulate the electronic structure of NiPt NPs,thereby boosting the catalytic performance.Compared with NiPt/Y_(2)O_(3) and NiPt/rGO,the NiPt/Y_(2)O_(3)/rGO nanocomposites(NCs) show remarkable enhanced catalytic efficiency for hydrogen production from N_(2)H_(4)-H_(2)O.In particular,the optimized Ni_(0.6)Pt_(0.4/)Y_(2)O_(3)/rGO NCs display the best catalytic efficiency and 100% H_(2) selectivity for N_(2)H_(4)-H_(2)O dehydrogenation,providing a turnover frequency(TOF) of2182 h^(-1) at 323 K,which is among the highest values ever reported.Moreover,the Ni_(0.6)Pt_(0.4)/Y_(2)O_(3)/rGO NCs also exhibit an excellent catalytic performance(TOF=3191 h^(-1)) and 100% H_(2) selectively for N_(2)H_(4)BH_(3)dehydrogenation at 323 K.The outstanding catalytic results obtained provide more possibilities for the potential applications of N_(2)H_(4)·H_(2)O and N_(2)H_(4)BH_(3) as promising chemical hydrogen storage materials.

Facile synthesis of graphene-supported Ni-CeOx nano-composites as highly efficient catalysts for hydrolytic dehydrogenation of ammonia borane

Development of low-cost and high-performance catalysts for hydrogen generation via hydrolysis of ammonia borane （NH3BH3, AB） is a highly desirable pathway for future hydrogen utilization. In this work, Ni nanocatalysts doped with CeOx and supported on graphene （Ni-CeOdgraphene） were synthesized via a facile chemical reduction route and applied as robust catalysts for the hydrolysis of AB in aqueous solution at room temperature. The as-synthesized Ni-CeOdgraphene nanocomposites （NCs） exhibited excellent catalytic activity with a turnover frequency （TOF） as high as 68.2 min-1, which is 49-fold higher than that for a simple Ni nanoparticle catalyst and is among the highest values reported for non-noble metal catalysts in AB hydrolysis. The development of efficient and low-cost Ni-CeOdgraphene catalysts enhances the feasibility of using ammonia borane as a chemical hydrogen storage material, which may find application in a hydrogen fuel-cell based economy.

2022 roadmap on hydrogen energy from production to utilizations

Hydrogen has been always the hot topic,which drives a lot of researchers to study and explore hydrogenrelated projects and fields.The first subfield is hydrogen production with green and cost-effective means.Some methods have been intensively used for high-efficient hydrogen production,i.e.,catalytic chemical hydrogen generation,electrocatalytic hydrogen evolution,photocatalytic hydrogen evolution,photo-electrocatalytic hydrogen evolution.Most of them are driven by various catalysts.Moreover,the hydrogen storage is also an important question,which is also a present research hot topic,although the history is long with several decades.Hydrogen fuel cells have also obtained great attention due to the zero emissions.The related research mainly focuses on the cell systems and electrocatalysts used.Under this background,we invite some excellent research groups to write this progress on hydrogen from production to utilizations.Finally,we believe that this roadmap on hydrogen can give some useful guidance in future research.

Robust hydrogen production from HCOOH over amino-modified KIT-6-confined Pd Ir alloy nanoparticles

Formic acid (FA), which can be produced via CO_(2) reduction and biomass conversion, has received extensive interest as a convenient and safe hydrogen carrier due to its wide range of sources, renewable, high hydrogen content (4.4 wt%), and convenient storage/transportation. Designing highly efficient catalysts is the main challenge to realize the hydrogen production from FA. In this work, well-dispersed and electron-rich PdIr alloy nanoparticles with a size of 1.8 nm are confined in amino-modified 3D mesoporous silica KIT-6 and applied as a highly efficient catalyst for robust hydrogen production from FA at ambient temperature. Small PdIr alloy nanoparticles confined by amino-modified KIT-6 (PdIr/KIT-6-NH_(2)) lead to better catalytic activity compared to that of Pd/KIT-6-NH_(2) and PdIr confined by bare KIT-6, achieving a high turnover frequency (TOF) value of 3533 h-1 at ambient temperature (303 K), 100% H_(2) selectivity and conversion toward the dehydrogenation of FA, which is comparable to the best heterogeneous catalysts ever reported. The high catalytic activity of PdIr/KIT-6-NH_(2) can be attributed to the synergistic effect between Pd and Ir, strong interaction between PdIr and KIT-6-NH_(2), as well as the amino-groups of KIT-6-NH_(2) which can act as a proton scavenger to promote the breaking of O-H bond of formic acid.