Design Of Inorganic Nanomaterials And Their Applications In Hydrogen Evolution Reaction And Alcohol Oxidation Reaction

Energy is an important material basis for the survival and development of human society.To improving the energy efficiency and solving energy problems,high performance,selectivity and stability electrocatalysts were of importance.Hydrogen evolution reaction and alcohol oxidation reaction are fundamental reactions to new generation of green energy conversion devices.Some achievements were obtained through lots of investigations in the last decades.However,cheap and high performance electrocatalysts for hydrogen evolution reaction were conducive to the application of hydrogen energy.Besides,activity decay quickly and poor selectivity toward the C-C cleavage of the alcohol oxidation electrocatalysts have not yet been resolved satisfactorily.As for the unique structure and synergistic effect between different components,inorganic nano-electrocatalysts have been obtained more and more attention in catalysis.In this paper,inorganic nano-electrocatalysts were prepared by simple methods,such as transition metal tungsten disulfide catalysts and different Pt、Pd-based catalyst,and we further investigated the electrochemical performance and reaction mechanism of these electrocatalysts.The preparation and electrocatalytic properties of ultra-thin WS₂ catalysts,Pt/Ni（OH）₂/rGO catalysts,Pd/Ni（OH）₂/rGO catalysts,and 2D PdAg catalysts were introduced,and the reaction mechanism of the above catalysts needed to be further explored.The work of this paper includes the following sections:1.Ultra-thin WS₂ nanosheet electrocatalysts were prepared by a high-temperature solution phase method for the electrocatalytic hydrogen evolution reaction.Ultra-thin WS₂ nanosheet catalysts have favorable single-layer nanostructure and abundant edge sites,demonstrating splendid performance for hydrogen evolution reaction.Ultrathin WS₂ nanosheet electrocatalysts has a small overpotential of?100 mV,and the Tafel slope is 48 mV dec^-1.After a continuous 10,000 cycle stability measurement,the catalytic activity of WS₂ was still desirable.Ultrathin WS₂ nanosheet electrocatalysts is an attractive electrocatalysts for hydrogen evolution reaction and an excellent candidate for replacement Pt-based catalysts.2.The Pt/Ni（OH）₂/rGO ternary hybrids catalyst were prepared by a simple two-step method with the size of Pt particles was 2?3 nm,and they were uniformly distributed on the surface of the Ni（OH）₂/GO.Due to the promoting effect of Ni（OH）₂,the reasonable spatial distribution among the three components and the strong mutual synergy effect,the hybrids electrocatalysts exhibit excellent methanol oxidation activity and stability.The specific current of ternary hybrids for methanol oxidation still maintained at 400 mA mg_Pt^-1 after continuous 50,000 s stability measurement.Besides,the hybrids electrocatalysts can be simply reactivated by a few CV cycles in 1 M KOH after the 50,000 s durability measurement to recover full MOR activity to the initial value and then is ready for another 50,000 s continuous operation in a fresh methanol electrolyte.As for as we known,the stability of our hybrids electrocatalysts two to three orders of magnitude longer than all available electrocatalysts.3.The Ni（OH）₂-modified Pd/rGO catalyst was prepared via a similar two-step process.Due to the promotion of Ni（OH）₂,the Pd/Ni（OH）₂/rGO hybrids electrocatalysts appeared excellent performance for ethanol oxidation reaction in alkaline medium.The specific current of Pd/Ni（OH）₂/rGO hybrids was still 440 mA mg_Pd^-1 after 20,000 s long-term stability measurement.Besides,the performance of Pd/Ni（OH）₂/rGO hybrids can be regeneration through simply reactivated,And it can be operated another 20,000 s long-term stability measurements.In-situ attenuated total reflection infrared experiments combined with ion chromatography for investigation the process of ethanol oxidation reaction found that,our hybrids electrocatalysts have excellent resistance to CO poison.Besides,our hybrids catalysts shown enhanced selectivity C1 pathway than any other Pd-based electrocatalysts at room temperature.4.The 2D PdAg nanodendried electrocatalysts were synthesized via a simple solution method at room temperature.Octadecyltrimethylammonium chloride（OTAC）surfactant was an important structure directing agent for the two-dimensional nanodendritic structure.The obtained 2D PdAg nanodendried electrocatalysts have a small thickness of 5?7 nm,and the pretty branches were distributed randomly in-plane.On account of enlarged surface areas,abundant under-coordinated sites and the synergistic effect between Pd and Ag,2D PdAg nanodendried electrocatalysts exhibits excellent ethanol oxidation performance at alkaline conditions with a peak specific current of up to 2,600 mA mg_Pd^-1,and outstanding chronoamperometry（i?t）stability and cycle stability.