A new phase of 1T-phase platinum oxide exhibits a record acidic HER activity. A mechanism whereby the [Pt–O] active site can be easily attacked by protons to form the Pt–H intermediate state during the HER is proposed.
The development of palladium‐based catalysts for alkaline hydrogen evolution reaction (HER) is highly desired for renewable hydrogen energy systems, yet still challenging due to the strong palladium–hydrogen bond. Herein, the bottleneck is largely overcome by constructing a nitridation‐induced compressively strained‐interface N‐doped palladium/amorphous cobalt (II) interface (N‐Pd/A‐Co(II)), which dramatically boosts HER performance in alkaline condition. The optimized catalyst with the compressive strain of 2.7% exhibits the higher activity with an overpotential of only 58 mV to achieve the current density of 10 mA cm−2, much better than those of pure Pd (327 mV), and the state‐of‐art Pt/C (78 mV). Notably, it also shows excellent stability with negligible decline during a 30 h stability test. Detailed analyses reveal that the strong absorption of Hads on Pd can be efficiently reduced via the compressively strained N‐doped Pd. And the amorphous Co(II) component accelerates the water dissociation. Consequently, the cooperative effect between the compressed N‐doped Pd and amorphous Co(II) creates the impressive HER performance in alkaline condition, highlighting the importance of the functional interface to develop efficient electrocatalysts for HER and beyond.
Designing a unique metastable interface
provides a promising way
to achieve high catalytic performance yet remains a great challenge
due to the thermodynamics’ unstable nature. In this work, we
constructed the stabilized metastable interface between metastable
ruthenium–nickel alloy and metastable hexagonal–close-packed
nickel via a one-step solvothermal method. The optimized nanocatalyst
(denoted as hcp RuNi) shows bifunctional performance toward electrochemical
hydrogen oxidation and evolution reactions (HOR/HER). Density functional
theory calculations reveal that two different reaction sites at the
unique interface contribute to the enhanced HER and HOR performances.
This work highlights the important role on interface engineering of
metastable materials for highly efficient catalysis.
The mechanisms occurring in a photolytic circulating-bed biofilm reactor (PCBBR) treating 2,4,6-trichlorophenol (TCP) were investigated using batch experiments following three protocols: photodegradation alone (P), biodegradation alone (B), and intimately coupled photodegradation and biodegradation (P&B). Initially, the ceramic particles used as biofilm carriers rapidly adsorbed TCP, particularly in the B experiments. During the first 10 min, the TCP removal rate for P&B was equal to the sum of the rates for P and B, and P&B continued to have the greatest TCP removal, with the TCP concentration approaching zero only in the P&B experiments. When phenol, an easily biodegradable compound, was added along with TCP in order to promote TCP mineralization by means of secondary utilization, P&B was superior to P and B in terms of mineralization of TCP, giving 95% removal of chemical oxygen demand (COD). The microbial communities, examined by clone libraries, changed dramatically during the P&B experiments. Whereas Burkholderia xenovorans, a known degrader of chlorinated aromatics, was the dominant strain in the TCP-acclimated inoculum, it was replaced in the P&B biofilm by strains noted for biofilm formation and biodegrading non-chlorinated aromatics.
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