In Situ Generation and Stabilization of Accessible Cu/Cu₂O Heterojunctions inside Organic Frameworks for Highly Efficient Catalysis

Abstract

Heterostructural metal/metal oxides are the very promising substituents of noble‐metal catalysts; however, generation and further stabilization of accessible metal/metal oxide heterojunctions are very difficult. A strategy to encapsulate and stabilize Cu/Cu2O nanojunctions in porous organic frameworks in situ is developed by tuning the acrylate contents in copper‐based metal–organic frameworks (Cu‐MOFs) and the pyrolytic conditions. The acrylate groups play important roles on improving the polymerization degree of organic frameworks and generating and stabilizing highly dispersed and accessible Cu/Cu2O heteronanojunctions. As a result, pyrolysis of the MOF ZJU‐199, consisting of three acrylates per ligand, generates abundant heterostructural Cu/Cu2O discrete domains inside porous organic matrices at 350 °C, demonstrating excellent catalytic properties in liquid‐phase hydrogenation of furfural into furfuryl alcohol, which are much superior to the non‐noble metal‐based catalysts.

Interwrapping Distinct Metal-Organic Frameworks in Dual-MOFs for the Creation of Unique Composite Catalysts

“…The thermal behaviors of HKUST-1/ZIF-8 were monitored by TG-MS measurement under N 2 atmosphere (Figure 3(a) and Figures S17-S21). Upon raising the annealing temperature, a weight loss is observed in the temperature range of 200-450°C, which is similar to that of HKUST-1, indicating that the weight loss is derived from decarboxylation of the carboxylate linkers in HKUST-1 [28]. When the temperature was raised above 550°C, the TG curve sharply decayed, which is similar to the thermal behaviors of phase-pure ZIF-8 [29].…”

Dandelion-Like Nanostructured Cu/Cu2O Heterojunctions with Fast Diffusion Channels Enabling Rapid Photocatalytic Pollutant Removal

“…The oscillating satellite peak at 943.0 eV confirms the existence of Cu 2+ , and the stronger intensity indicates that the Cu 2+ content of Cu/Cu 2 O-4 is higher than that of Cu/Cu 2 O-8. 10,18,54,55 Restricted by the low crystallinity and content of Cu 2+ , no obvious diffraction peak belonging to CuO or Cu(OH) 2 can be observed in Figure 1b. From the XPS data, the [(Cu 0 + Cu + )/Cu 2+ ] atomic ratios for Cu/Cu 2 O-4 and Cu/Cu 2 O-8 can be calculated as 2.50 and 3.88, respectively.…”

Research progress on the role of common metal catalysts in biomass pyrolysis: a state-of-the-art review

“…In addition, Cu is easy to accumulate into clusters, leading to its poor catalytic effect when it exists alone, 171 but heterostructures with mixed valence states may be formed during the preparation of Cu-based catalysts, such as Cu/Cu 2 O, Cu 2 O/CuO and Cu/Cu 2 O/CuO. 172 Compared with isolated single-phase Cu or CuO x , a Cu/CuO x heterostructure can adjust the electron density of active sites, thereby improving the catalytic activity of each phase. However, Cu is easily oxidized to form a CuO x coating, so this structure requires a certain support to form, such as γ-Al 2 O 3 , 145 molecular sieve, 173 SiO 2 , 174 biochar, 175 nitrogen-containing carbon framework (NCF), 170 or organic supports (to prepare Metal–organic frameworks (MOFs)).…”