No abstract

A direct and effective approach is proposed to fabricate bimetallic phosphide Ni 2 P−Cu 3 P with controllable phase composition and distribution for catalytic hydrogen evolution reaction (HER). Unlike previously reported precursors, a porous Ni−Cu alloy incorporated with graphitic carbon (NiCuC) prepared via powder metallurgy is employed herein, and the generated Ni 2 P−Cu 3 P@NiCuC possesses a hierarchical porous structure and controllable phase composition due to the high porosity and tunable Ni/Cu ratio of the precursor. With an optimal Cu content of 30.0 wt %, the catalyst demonstrates the highest catalytic activity due to a synergistic interaction between different metallic phosphide sites and the facilitated mass transport. Meanwhile, density functional theory (DFT) calculation reveals that the atomic interaction of Ni 2 P− Cu 3 P substantially lower the activation barrier for enhanced HER catalytic activity. The powder metallurgy provides an approach for the design of bimetallic phosphide electrocatalysts for HER and other catalytic applications.

Polymerase chain reaction (PCR) has been a defining tool in modern biology. Towards realizing mirror-image PCR, we have designed and chemically synthesized a mutant version of the 352-residue thermostable Sulfolobus solfataricus P2 DNA polymerase IV with l-amino acids and tested its PCR activity biochemically. To the best of our knowledge, this enzyme is the largest chemically synthesized protein reported to date. We show that with optimization of PCR conditions, the fully synthetic polymerase is capable of amplifying template sequences of up to 1.5 kb. The establishment of this synthetic route for chemically synthesizing DNA polymerase IV is a stepping stone towards building a d-enzyme system for mirror-image PCR, which may open up an avenue for the creation of many mirror-image molecular tools such as mirror-image systematic evolution of ligands by exponential enrichment.