Series of pure-phase ordered palladium-boron intermetallic compounds, preparation method and application thereof

Abstract

The invention discloses a series of pure-phase ordered palladium-boron intermetallic compounds, a preparation method and application thereof in the aspect of efficient electrocatalytic water splittinghydrogen production, which belong to the technical field of electrocatalyst preparation. The preparation method comprises the following steps of firstly, sealing precursor salts of palladium and boron in a glass tube by utilizing a vacuum tube sealing technology, calcining at a certain temperature to generate replacement reaction, and performing acid treatment to obtain pure-phase ordered Pd2B, Pd5B2 and Pd3B palladium-boron intermetallic compounds which are of hexagonal close packing phase structures. Boron atoms are located in an octahedral structure constructed by palladium atoms, the center of a d band of Pd is moved upwards due to the strong bonding effect and orbital hybridization effect between boron and palladium on the subsurface, and the intermetallic compound shows excellent catalytic activity stability in the aspect of hydrogen production through electro-catalytic water splitting. The overpotential of Pd2B only needs 18 mV to reach the current density of 10 mA/cm<2> duringelectrocatalytic water splitting hydrogen evolution, so that the potential of replacing a noble metal catalyst Pt is shown to a certain extent, and the application prospect is wide.

Description

Technical field[0001]The invention belongs to the technical field of electrocatalyst preparation, and specifically relates to a series of pure-phase ordered palladium-boron intermetallic compounds, a preparation method and its application in high-efficiency electrocatalytic water splitting hydrogen production.Background technique[0002]Pd is widely used in catalytic reaction technologies involving hydrogenation and dehydrogenation, such as biomass conversion, electrocatalysis, selective hydrogenation of acetylene, and Suzuki reaction. Due to the surface stereo effect, low coordination, and a large number of voids that can accommodate hydrogen atoms, Pd has strong adsorption of reactive molecules and is not easy to desorb, which leads to a decrease in the selectivity and activity of Pd, making it useful as a catalyst The significance of existence is greatly reduced. According to reports, boron occupies the interstitial position of the metal lattice and can effectively regulate the cat...

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Problems solved by technology

[0003] In the currently synthesized palladium-boron materials, the arrangement of boron atoms in the palladium lattice is disordered (J.Am.Chem.Soc. 2009, Volume 141, page 19616), which makes it difficult for us to accurately obtain atomic Precise position in the metal interstitial, and at the same time, the concentration of interstitial boron atoms cannot be strictly controlled, so it is difficult to control the boron element in the lattice at the atomic level

However, the synthesis of palladium boron intermetallic compounds with ordered arrangement of boron atoms is very difficult

First, atomically ordered palladium-boron intermetallic compounds are prepared using the traditional high-temperature and high-pressure arc method, under very harsh conditions

Secondly, the component content and formation energy of ordered intermetallic compounds of different phases are close, which makes it easy to form multi-phase mixed metal borides, making it very difficult to synthesize pure phase intermetallic compounds

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