Title: Combinatorial Search for High-Activity Hydrogen Catalysts Based on Transition-Metal-Embedded Graphitic Carbons

Abstract

Transition metal (TM) atoms in porphyrin–like complexes play important roles in many protein and enzymetic systems, where crystal–field effects are used to modify d–orbital levels. Inspired by the tunable electronic structure of these motifs, a high–throughput computational search for synthetic hydrogen catalysts is performed based on a similar motif of TM atoms embedded into the lattice of graphene. Based on an initial list of 300 possible embedding geometries, binders, and host atoms, descriptors for stability and catalytic activity are applied to extract ten promising candidates for hydrogen evolution, two of which are expected to exhibit high activity for hydrogen oxidation. In several instances, the active TM atoms are earth–abundant elements that show no activity in the bulk phase, highlighting the importance of the coordination environment in tuning the d–orbitals. In conclusion, it is found that the most active candidates involve a hitherto unreported surface reaction pathway that involves a Kubas–complex intermediate, which significantly lowers the kinetic barrier associated with hydrogen dissociation and association.

Authors:

Choi, Woon Ih ^[1]; Wood, Brandon C. ^[2]; Schwegler, Eric ^[2]; Ogitsu, Tadashi ^[2]

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+ Show Author Affiliations

1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Samsung Advanced Institute of Technology, Gyeonggi-do (South Korea)
2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Publication Date:

2015-09-22

Research Org.:

Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1438765

Report Number(s):

LLNL-JRNL-737906
Journal ID: ISSN 1614-6832

Grant/Contract Number:  

AC52-07NA27344

Resource Type:

Accepted Manuscript

Journal Name:

Advanced Energy Materials

Additional Journal Information:

Journal Volume: 5; Journal Issue: 23; Journal ID: ISSN 1614-6832

Publisher:

Wiley

Country of Publication:

United States

Language:

English

Subject:

08 HYDROGEN; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; computational high-throughput screening; density functional theory calculations; graphene; hydrogen catalysts; transition metals