Heterogeneous Hydrogenation with Hydrogen Spillover Enabled by Nitrogen Vacancies on Boron Nitride‐Supported Pd Nanoparticles

Abstract

Heterogeneous hydrogenation with hydrogen spillover has been demonstrated as an effective route to achieve high selectivity towards target products. More effort should be paid to understand the complicated correlation between the nature of supports and hydrogenation involving hydrogen spillover. Herein, we report the development of the hydrogenation system of hexagonal boron nitride (h‐BN)‐supported Pd nanoparticles for the hydrogenation of aldehydes/ketones to alcohols with hydrogen spillover. Nitrogen vacancies in h‐BN determine the feasibility of hydrogen spillover from Pd to h‐BN. The hydrogenation of aldehydes/ketones with hydrogen spillover from Pd proceeds on nitrogen vacancies on h‐BN. The weak adsorption of alcohols to h‐BN inhibits the deep hydrogenation of aldehydes/ketones, thus leading to high catalytic selectivity to alcohols. Moreover, the hydrogen spillover‐based hydrogenation mechanism makes the catalyst system exhibit a high tolerance to CO poisoning.

Hydrogen spillover on N-doped carbon coating improves the hydrogenation performance of nickel catalysts

“…This might indicate that all the Ni sites responsible for the H 2 cleavage and alkyne reduction are protected by the N-doped carbon coating. Another possibility is that our system presents a similar CO poisoning resistance due to a spillover phenomenon reported by Zhang et al , 12 in which the activity of benzaldehyde hydrogenation was preserved with 2 eq. CO : Pd, corroborated by the increase of selectivity due to the inhibition of “free” Pd.…”

Construction of Boron‐ and Nitrogen‐Enriched Nanoporous π‐Conjugated Networks Towards Enhanced Hydrogen Activation

“…To further study the role of active B or N sits within the BN‐NCN‐750 scaffolds in the hydrogenation reactions, the quenching experiments were conducted by adding additives to block and deactivate the Lewis acidic B or Lewis basic N sites in the phenylacetylene hydrogenation. First, 2,2‐Diphenyl‐1‐picrylhydrazyl (DPPH), which has a strong affinity for binding B atoms in nitrogen vacancies, was applied to deactivate the active B sites over BN‐NCN‐750 (BN‐NCN‐750‐DPPH) [71] . Under the same reaction conditions, BN‐NCN‐750‐DPPH exhibited significantly decreased catalytic activity compared with the original BN‐NCN‐750 catalyst, with 52 % conversion of A, 48 % yield of B, and 4 % yield of C (Figure 4D), indicating that the active B sites played a key role in the hydrogenation reactions.…”

“…First, 2,2-Diphenyl-1picrylhydrazyl (DPPH), which has a strong affinity for binding B atoms in nitrogen vacancies, was applied to deactivate the active B sites over BN-NCN-750 (BN-NCN-750-DPPH). [71] Under the same reaction conditions, BN-NCN-750-DPPH exhibited significantly decreased catalytic activity compared with the original BN-NCN-750 catalyst, with 52 % conversion of A, 48 % yield of B, and 4 % yield of C (Figure 4D), indicating that the active B sites played a key role in the hydrogenation reactions. In addition, deactivating the Lewis base sites by dosing CO 2 into the reactor led to decreased catalyst performance, with 47 % conversion of A, 42 % yield of B, and 4 % yield of C being obtained.…”

Construction of Boron‐ and Nitrogen‐Enriched Nanoporous π‐Conjugated Networks Towards Enhanced Hydrogen Activation

“…First, 2,2-Diphenyl-1picrylhydrazyl (DPPH), which has a strong affinity for binding B atoms in nitrogen vacancies, was applied to deactivate the active B sites over BN-NCN-750 (BN-NCN-750-DPPH). [71] Under the same reaction conditions, BN-NCN-750-DPPH…”