Crystalline Lattice‐Confined Atomic Pt in Metal Carbides to Match Electronic Structures and Hydrogen Evolution Behaviors of Platinum

Abstract

oxidation, [3] the oxygen reduction reaction, [4] hydrogen oxidation reaction, [5] and hydrogen evolution reaction (HER). [6] The scarcity and high cost of Pt have necessitated the development of catalytic systems with increased activity, utilization, and durability of Pt atoms. In this respect, the increase of Pt dispersion on supports by downsizing metals to the atomic scale is of significance for maximizing the Pt utilization and consequently increasing the mass activity and turnover frequency (TOF). [7,8] However, in most cases, the electronic properties of the supported Pt atoms are highly dependent on coordination/supporting environments, which have been shown to be crucial for enabling the Pt catalysts with high intrinsic activity. [9] In recent years, abundant efforts have been made to synthesize the atomic Pt catalysts with tailored coordination environments on diverse supports, such as the N/S-doped carbon materials (Pt 1 /NC, [10] PtRuC [11] ), metal oxides (PtCoO, [12] PtFe 2 O 3 [13] ), metal sulfides (PtMoS 2 [14] ), etc. Anchoring Pt atoms by neighboring strong electronegative atoms will lead to a large charge transfer from Pt to coordinated O/N/S atoms, Platinum-based catalysts occupy a pivotal position in diverse catalytic applications in hydrogen chemistry and electrochemistry, for instance, the hydrogen evolution reactions (HER). While adsorbed Pt atoms on supports often cause severe mismatching on electronic structures and HER behaviors from metallic Pt due to the different energy level distribution of electron orbitals.Here, the design of crystalline lattice-confined atomic Pt in metal carbides using the Pt-centered polyoxometalate frameworks with strong PtO-metal covalent bonds is reported. Remarkably, the lattice-confined atomic Pt in the tungsten carbides (Pt doped @WC x , both Pt and W have atomic radii of 1.3 Å) exhibit near-zero valence states and similar electronic structures as metallic Pt, thus delivering matched energy level distributions of the Pt 5d z 2 and H 1s orbitals and similar acidic hydrogen evolution behaviors. In alkaline conditions, the Pt doped @WC x exhibits 40 times greater mass activity (49.5 A mg Pt −1 at η = 150 mV) than the Pt@C because of the favorable water dissociation and H* transport. These findings offer a universal pathway to construct urgently needed atomic-scale catalysts for broad catalytic reactions.

Microwave Synthesis of Pt Clusters on Black TiO2 with Abundant Oxygen Vacancies for Efficient Acidic Electrocatalytic Hydrogen Evolution

“…Similarly, Cheng and co-authors demonstrate that the metal carbides (WC and MoC) also could enhance the utilization efficiency of Pt species. [45] Owing to its abundance and good physiochemical properties, TiO 2 has been widely investigated as a substrate for the deposition of noble metals to optimize the catalytic properties. [46][47][48] Relative to TiO 2 , oxygen vacancies enriched black TiO 2 has received tremendous attentions, [49][50][51] particularly for photocatalytic reactions, [52][53][54][55][56][57][58] owing to the narrowed band gap.…”

B4C enhances the supported platinum DER/HER performance

“…The support has the role of dispersing and anchoring the active component, and the interaction force between different supports and the active component varies; thus, the choice of support is equally important. Carbides have been widely studied as typical electrocatalytic supports, 23,24 including carbides such as Mo 2 C, 25–28 WC, 29,30 TiC, 31 and Ni 3 C; 32 they have stronger interactions with metals than carbon, 33 and can provide stronger interaction forces. Among them, boron carbide (B 4 C) is a nonmetallic carbide; it is one of the most stable substances toward acid and has the advantages of a high melting point and good electrical conductivity.…”

The enhancement in the performance of ultra-small core–shell Au@AuPt nanoparticles toward HER and ORR by surface engineering

“…Pt-based catalysts are still the most potential catalysts with excellent performance toward the hydrogen evolution reaction (HER) and the oxygen reduction reaction (ORR) in acidic media. [1][2][3][4][5][6] To further boost their catalytic performance, many efforts have been made to synthesize Pt-based catalysts by controlling their sizes, [7][8][9][10][11] shapes, [12][13][14][15][16] structures, [17][18][19][20][21][22][23] and tuning surface compositions. [24][25][26][27][28][29][30] For instance, ultra-small core-shell Au-Pt nanoparticles (USCS Au@AuPt NPs) with Au-rich cores and Pt-rich shells previously reported in our work exhibit excellent electrocatalytic performance toward the HER and ORR in acidic media due to the higher electrochemically active surface area (ECSA) resulting from their small sizes and electronic effect between Pt and Au.…”