Integration of Quantum Confinement and Alloy Effect to Modulate Electronic Properties of RhW Nanocrystals for Improved Catalytic Performance toward CO₂ Hydrogenation

Abstract

The d-band center and surface negative charge density generally determine the adsorption and activation of CO, thus serving as important descriptors of the catalytic activity toward CO hydrogenation. Herein, we engineered the d-band center and negative charge density of Rh-based catalysts by tuning their dimensions and introducing non-noble metals to form an alloy. During the hydrogenation of CO into methanol, the catalytic activity of RhW nanosheets was 5.9, 4.0, and 1.7 times as high as that of Rh nanoparticles, Rh nanosheets, and RhW nanoparticles, respectively. Mechanistic studies reveal that the remarkable activity of RhW nanosheets is owing to the integration of quantum confinement and alloy effect. Specifically, the quantum confinement in one dimension shifts up the d-band center of RhW nanosheets, strengthening the adsorption of CO. Moreover, the alloy effect not only promotes the activation of CO to form CO but also enhances the adsorption of intermediates to facilitate further hydrogenation of the intermediates into methanol.

Tungsten as “Adhesive” in Pt2CuW0.25 Ternary Alloy for Highly Durable Oxygen Reduction Electrocatalysis

“…The elemental mapping and line-scan profiles obtained by energy-dispersive X-ray spectroscopy (EDX) using high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) indicate the distribution of Pt, Cu, and W, as shown in Figure 1c,d. [29] The molar ratios of Pt/Cu/W are determined through inductively coupled plasma optical emission spectrometer (ICP-OES), as shown in Figure S2 in the Supporting Information. [29] The molar ratios of Pt/Cu/W are determined through inductively coupled plasma optical emission spectrometer (ICP-OES), as shown in Figure S2 in the Supporting Information.…”

New Aspects of Platinum Group Metal‐Based Solid‐Solution Alloy Nanoparticles: Binary to High‐Entropy Alloys

“…However, at the same time, such huge differences in the intrinsic nature also hinder the alloying process. For most ETMs, wet chemistry methods are not available for the formation of a solid‐solution alloy at all, except for a few reported cases for V, Cr, Mo, W, and others.…”

“…W‐based PGMs such as Rh‐W, Ir‐W, and Pd‐W have been obtained based on a strategy combining a process of thermal decomposition and atomic diffusion. Zeng et al.…”

“…Zeng et al. successfully prepared a series of Rh x W 1− x (0≤ x ≤64) nanosheets by a two‐step process . First, Rh(acac) 3 was dissolved in a mixture of diphenyl ether, OAm, and oleic acid (OAc) and then preheated to 220 °C for 5 min.…”

“… a) STEM images and b) EDX maps of overlapped Rh and W of Rh 75 W 25 ss nanosheets (adapted from ref. ). c) Bright‐field TEM image, d) atomic‐resolution STEM image, e) high‐resolution TEM image, and f) EDX overlapped maps of Ir‐W ss nanoflowers (adapted from ref.…”