Impact of d-Band Occupancy and Lattice ... - ACS Publications

Nov 17, 2015 - convenience, L12 structure has been assumed for all the Pd3M models in this ... activation energy barriers for the surface segregation ...
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Impact of d‑Band Occupancy and Lattice Contraction on Selective Hydrogen Production from Formic Acid in the Bimetallic Pd3M (M = Early Transition 3d Metals) Catalysts Sangheon Lee,† Jinwon Cho,†,§ Jong Hyun Jang,† Jonghee Han,†,§ Sung Pil Yoon,† Suk Woo Nam,†,§ Tae Hoon Lim,† and Hyung Chul Ham*,†,‡ †

Fuel Cell Research Center, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea ‡ Clean Energy and Chemical Engineering, University of Science and Technology (UST), 217 Gajungro, Yuseong-gu, Daejeon, 305-333, Republic of Korea § Green School (Graduate School of Energy and Environment), Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 136-701, Republic of Korea S Supporting Information *

ABSTRACT: Catalysts that are highly selective and active for H2 production from HCOOH decomposition are indispensable to realize HCOOH-based hydrogen storage and distribution. In this study, we identify two effective routes to promoting the Pd catalyst for selective H2 production from HCOOH by investigating the effects of early transition metals (Sc, Ti, V, and Cr) incorporated into the Pd core using density functional theory calculations. First, the asymmetric modification of the Pd surface electronic structure (dz2 vs dyz + dzx) can be an effective route to accelerating the H2 production rate. Significant charge transfer from the subsurface Sc atom to the surface Pd atom and subsequent extremely low level of d band occupancy (