Analysis of Distribution and Structures of Heteroatom Compounds in Asphaltene of Medium/Low Temperature Coal Tar by Negative Anion Mode ESI FT-ICR MS

The existence of heteroatomic compounds with complex structure and different polarity in the asphaltene of medium and low temperature coal tar (M/LTCT) limits its processing and utilization. Combined with negative ion electrospray ionization source (ESI), Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to characterize the molecular composition of O, N, and S heteroatom compounds in M/LTCT asphaltenes. Acidic oxygen-containing compounds (OCCs) and non-basic nitrogen-containing compounds (NCCs) in asphaltenes were identified, except for sulfur-containing compounds (SCCs). The mass spectra showed that the heteroatom compounds in asphaltene mainly existed as NX, N1OX, N2OX, N3OX, N4OX, N5OX, N6OX, and OX class species (where x = 1–6). The M/LTCT asphaltenes were enriched with O4, N4, and N1O1 class species. The core structure of O4 class species were likely to be composed of 1–7 aromatic rings with 4 phenolic hydroxyl groups, the core structure of N4 class species were likely to be comprised of 4–7 aromatic rings with a piperazine ring and a pyrazole ring, and the core structure of N1O1 was mainly 3–6 aromatic rings with a phenolic hydroxyl group and a pyrrole ring. These results suggest that more condensed NCCs and OCCs with short, substituted alky side chains are presented, which are more easily to undergo condensation to generate fused molecules, making it too difficult to be removed by hydrogenation. Through the analysis of the molecular structures of OCCs and non-basic NCCs in M/LTCT asphaltenes, important information about the molecular composition can be obtained, which can provide basic data for the hydrogenation of deasphaltene

An electron-hole rich dual-site nickel catalyst for efficient photocatalytic overall water splitting

Vast majority of photocatalysts for hydrogen production relies on additional sacrificial agents and noble metal cocatalysts. It is of great importance yet challenging to achieve photocatalytic overall water splitting with decent performance. Here, the authors report Ni2P based photocatalyst assisted by H2O2-craking reaction for overall water splitting with H2 and O2 production of 1507 μmol h−1 g−1 H2 and 702 μmol h−1 g−1

Analysis of Distribution and Structures of Heteroatom Compounds in Asphaltene of Medium/Low Temperature Coal Tar by Negative Anion Mode ESI FT-ICR MS

The existence of heteroatomic compounds with complex structure and different polarity in the asphaltene of medium and low temperature coal tar (M/LTCT) limits its processing and utilization. Combined with negative ion electrospray ionization source (ESI), Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to characterize the molecular composition of O, N, and S heteroatom compounds in M/LTCT asphaltenes. Acidic oxygen-containing compounds (OCCs) and non-basic nitrogen-containing compounds (NCCs) in asphaltenes were identified, except for sulfur-containing compounds (SCCs). The mass spectra showed that the heteroatom compounds in asphaltene mainly existed as NX, N1OX, N2OX, N3OX, N4OX, N5OX, N6OX, and OX class species (where x = 1–6). The M/LTCT asphaltenes were enriched with O4, N4, and N1O1 class species. The core structure of O4 class species were likely to be composed of 1–7 aromatic rings with 4 phenolic hydroxyl groups, the core structure of N4 class species were likely to be comprised of 4–7 aromatic rings with a piperazine ring and a pyrazole ring, and the core structure of N1O1 was mainly 3–6 aromatic rings with a phenolic hydroxyl group and a pyrrole ring. These results suggest that more condensed NCCs and OCCs with short, substituted alky side chains are presented, which are more easily to undergo condensation to generate fused molecules, making it too difficult to be removed by hydrogenation. Through the analysis of the molecular structures of OCCs and non-basic NCCs in M/LTCT asphaltenes, important information about the molecular composition can be obtained, which can provide basic data for the hydrogenation of deasphaltene

Visible-Light-Activated Suzuki–Miyaura Coupling Reactions of Aryl Chlorides over the Multifunctional Pd/Au/Porous Nanorods of CeO₂ Catalysts

Activation of aryl chlorides for Suzuki–Miyaura coupling (SMC) reactions is particularly challenging for heterogeneous catalysts due to the chemically inert nature of the C–Cl bond. Herein, the multifunctional Pd/Au/porous nanorods of CeO₂ (<i>PN</i>-CeO₂) catalysts with a well-defined spatial configuration deliver the first example of heterogeneous catalysts to activate the strong C–Cl bond under the irradiation of visible light (>400 nm) at room temperature. <i>PN</i>-CeO₂ with strong basicity not only provides the photogenerated electrons to enrich the electron density of metal nanoparticles but also generates holes for activation of arylboronic acids. Meanwhile, due to the strong local surface plasma resonance, the hot electrons from Au nanoparticles excited by visible light can be injected into Pd nanocatalysts that are spatially contacted with Au nanoparticles. Thus, Pd nanocatalysts with significantly enriched electron density efficiently activate the aryl chlorides under the visible light irradiation at room temperature. The high catalytic activity and reusability of multifunctional photocatalysts associated with full use of the photogenerated electrons and holes inspire the future exploitation for the activation of unreactive chemical bonds under mild conditions

Design of N‑Coordinated Dual-Metal Sites: A Stable and Active Pt-Free Catalyst for Acidic Oxygen Reduction Reaction

We develop a host-guest strategy to construct an electrocatalyst with Fe-Co dual sites embedded on N-doped porous carbon and demonstrate its activity for oxygen reduction reaction in acidic electrolyte. Our catalyst exhibits superior oxygen reduction reaction performance, with comparable onset potential (<i>E</i>_onset, 1.06 vs 1.03 V) and half-wave potential (<i>E</i>_1/2, 0.863 vs 0.858 V) than commercial Pt/C. The fuel cell test reveals (Fe,Co)/N-C outperforms most reported Pt-free catalysts in H₂/O₂ and H₂/air. In addition, this cathode catalyst with dual metal sites is stable in a long-term operation with 50 000 cycles for electrode measurement and 100 h for H₂/air single cell operation. Density functional theory calculations reveal the dual sites is favored for activation of O-O, crucial for four-electron oxygen reduction