Sustainable Synthesis of Dual Single‐Atom Catalyst of PdN₄/CuN₄ for Partial Oxidation of Ethylene Glycol

Abstract

Catalysts assumed that properly designed bimetallic systems would provide superior catalytic performance due to the cooperative effects between two atoms. Dual single-atom catalyst (DSAC) PdN 4 /CuN 4 is synthesized using a simple, cost-effective, and efficient electrochemical reduction method. The palladium single-atom is prepared first by electrochemical reduction of copper phthalocyanine to create defective N 4 sites. The new structural feature is characterized by copper reduction from Cu-N 4 coordination and the formation of defected N 4 (▫ M -N 4 ) sites, which react with a Pd precursor and form PdN 4 on the host surface. The DSAC PdN 4 /CuN 4 technique synergistically improves electrocatalytic performance toward the ethylene glycol oxidation reaction. It possesses excellent glycolate selectivity (above 88%) in an alkaline solution with an onset oxidation potential as low as 0.6 V versus a reversible hydrogen electrode, compared to commercial Pd/C. The DSAC electrocatalyst is characterized by its high current density of 83.92 mA cm −2 and high faradic efficiency value (>80%) for glycolate at 1.0 V RHE . The findings suggest a promising method to synthesize the DSACs in varying transition metals to achieve highly efficient, selective, and environmentally friendly catalysts for different applications.

Chalcogen Elements in Regulating the Local Electron Density of Cu2X for an Efficient Heterogeneous Fenton-like Process

“…The Cu 2p spectrum in Figure 1l shows that the characteristic peaks with the binding energies of 932.27 and 952.08 eV could be attributed to the Cu 2p 3/2 and Cu 2p 1/2 , respectively. 36 The above characteristics confirmed the successful synthesis of Cu 2 X (O, S, Se) catalysts.…”

“…Moreover, the XPS survey spectrum in Figure k further confirmed the presence of O, S, and Se elements in Cu 2 O, Cu 2 S, and Cu 2 Se, respectively. The Cu 2p spectrum in Figure l shows that the characteristic peaks with the binding energies of 932.27 and 952.08 eV could be attributed to the Cu 2p 3/2 and Cu 2p 1/2 , respectively . The above characteristics confirmed the successful synthesis of Cu 2 X (O, S, Se) catalysts.…”

Heteroatom-Coordinated Palladium Molecular Catalysts for Sustainable Electrochemical Production of Hydrogen Peroxide

“…The synchrotron-based Pd K-edge X-ray absorption near-edge structure (XANES) measurements were performed to investigate the atomic state and coordination environment of Pd in the molecular complexes Pd–N 4 –CO, Pd–S 4 –NCO, and Pd–N 2 O 2 –C, since the palladium single-atom catalysts exhibited homoleptic (same coordination) and heteroleptic (different coordination) coordination spheres, such as Pd–N 4 –CO, Pd–S 4 –NCO, and Pd–N 2 O 2 –C. As detailed in the literature, when palladium establishes coordination bonds with heteroatoms, such as nitrogen (N), oxygen (O), sulfur (S), and combinations of nitrogen with oxygen atoms, it leads to the development of a unique and well-defined atomistic structure configuration. − The extended X-ray absorption fine structure (EXAFS) at the K-edge of Pd was used to investigate the valence state and local coordination environment of individual palladium atoms in the catalysts Pd–N 4 –CO, Pd–S 4 –NCO, and Pd–N 2 O 2 –C. The Pd X-ray absorption near-edge structure (XANES) spectra revealed critical information regarding the atomic state of the catalysts Pd–N 4 –CO, Pd–S 4 –NCO, and Pd–N 2 O 2 –C (Figure a).…”

Inter‐Metal Interaction of Dual‐Atom Catalysts in Heterogeneous Catalysis

“…The Pd-N 4 /Cu-N 4 was synthesized by an electrochemical reduction approach, where copper phthalocyanine was reduced to form defective N 4 sites to anchor the Pd single-atom. [33] The Cu species on the surface were covered with OH À ions and donated electrons to Pd atoms. The electron-rich Pd species suppressed C-C bond cleavage and enabled selective production toward glycolate.…”

“…In addition, the defects on the substrate are also contributed to anchoring dual atoms. The Pd‐N 4 /Cu‐N 4 was synthesized by an electrochemical reduction approach, where copper phthalocyanine was reduced to form defective N 4 sites to anchor the Pd single‐atom [33] . The Cu species on the surface were covered with OH − ions and donated electrons to Pd atoms.…”