Selective acetylene hydrogenation as a vital industrial reaction has been studied for decades. However, some key issues remain elusive. Herein, a detailed microkinetic model using density functional theory energies is developed to comprehensively investigate the key aspects of acetylene hydrogenation on Pd(111). The coverage-dependent kinetic simulation, factoring in both self and cross-interactions of adsorbates as well as the coverage effects on the transition states of each elementary step, is compared with the coverage-independent kinetic calculation derived from energies obtained at low coverages. The accurate determination of the free-energy barrier of ethylene desorption using ab initio molecular dynamics (AIMD) with umbrella sampling adds further crucial insights into the microkinetic model. By combining the coverage-dependent calculations and AIMD results, we achieve a full first-principles kinetic simulation with all the kinetic parameters being systematically calculated to understand the acetylene hydrogenation. We show that the coverage-dependent microkinetic model gives a much more reasonable turnover frequency result of 1.41 s −1 at 300 K than that calculated using the coverage-independent model (3.16 × 10 −24 s −1 ). The microkinetic results, including activity and selectivity, are tested against the experimental data, yielding a good agreement. A comprehensive set of kinetic analyses is performed. It is found that the activity is mainly determined by the barriers of the first two hydrogenation steps. The step with the major effect on the reaction activity is gradually transitioned from the second hydrogenation step, C 2 H 3 * + H* ↔ C 2 H 4 * + *, to the first hydrogenation step of C 2 H 2 * + H* ↔ C 2 H 3 * + * as the temperature increases. Both the desorption barrier of ethylene and the hydrogenation barrier of C 2 H 4 * cause significant impacts on the selectivity of ethylene, but the former is found to be the most prominent physical quantity affecting the ethylene selectivity.

To advance a reliable microkinetic modeling approach using density functional theory (DFT) energies is of great importance to bridging between experimental results and theoretical calculations and the current major issue is the coverage effect. In this work, a full microkinetic modeling for NO oxidation using DFT energetics is developed. We show that the calculated TOF (0.22 s-1) agrees with the experimental one (~0.2 s-1) very well, if the coverage effects are properly incorporated. It is found that to include the interactions of adsorbates, namely (i) O and O, NO and NO (self-interaction) and (ii) O and NO (cross-interaction), is important to obtain accurate kinetic results. Equally important, the interactions between the adsorbates and the transition states of O-O bond breaking and O-NO coupling are also crucial for achieving precise kinetics. We demonstrate that a two-line model can be used to describe accurately both the self and cross adsorbate-adsorbate interactions as well as the coverage effects on the transition states of O2 dissociation and O-NO coupling. The various approximations including BEP relations are carefully examined and the errors involved are quantified. Moreover, a one-line model is tested, which is a simplified approach but gives rise to a good agreement with experimental results.

Exploring high-efficiency, low-cost, and stable photocatalysts that enable full solar spectrum including UV, visible, and near-infrared (NIR) light utilization for photocatalytic hydrogen generation still faces huge challenge. Herein, a Co 2 P/CdS Z-scheme photocatalyst without a noble metal is rationally fabricated to achieve ultrabroad UV−vis−NIR harvesting. Compared to Pt/CdS, CdS, and Co 2 P, the optimized Co 2 P/CdS exhibits much more outstanding performance with the H 2 generation rates of 262.16, 66.98, and 3.93 mmol/g/h under solar, visible (780 nm > λ > 420 nm), and NIR (λ > 780 nm) light, respectively. Particularly, 10% Co 2 P/CdS displays a prominent apparent quantum efficiency value of 2.26% at 700 nm. The Z-scheme transform route can effectively enhance the separation of charge carriers in Co 2 P/CdS for UV−vis-driven HER, as confirmed by photoluminescence and photoelectrochemical measurements. More importantly, the Co−S bonds at the interface demonstrated by Fourier transform infrared, Raman (mapping), and X-ray photoelectron spectroscopy and density functional theory calculations can act as a "bridge" for charge transfer, thereby enhancing the full spectrum-driven H 2 evolution. To the best of our knowledge, this is a rare research on full spectrum-driven photocatalytic HER without a noble metal.

Electrocatalytic urea synthesis is an emerging alternative technology to the traditional energy-intensive industrial urea synthesis protocol. Novel strategies are urgently needed to promote the electrocatalytic C–N coupling process and inhibit the side reactions. Here, we report a CuWO4 catalyst with native bimetallic sites that achieves a high urea production rate (98.5 ± 3.2 μg h−1 mg−1cat) for the co-reduction of CO2 and NO3− with a high Faradaic efficiency (70.1 ± 2.4%) at −0.2 V versus the reversible hydrogen electrode. Mechanistic studies demonstrated that the combination of stable intermediates of *NO2 and *CO increases the probability of C–N coupling and reduces the potential barrier, resulting in high Faradaic efficiency and low overpotential. This study provides a new perspective on achieving efficient urea electrosynthesis by stabilizing the key reaction intermediates, which may guide the design of other electrochemical systems for high-value C–N bond-containing chemicals.

An electrochemical nitrogen reduction reaction (NRR) under mild conditions offers a promising alternative to the traditional Haber–Bosch process in converting abundant nitrogen (N2) to high value-added ammonia (NH3). In this work, iron phthalocyanine (FePc) was homogeneously immobilized on pyridine-functionalized carbon nanotubes to form a well-tuned electrocatalyst with an FeN5 active center (FePc-Py-CNT). Synchrotron X-ray absorption and Fourier transform infrared spectroscopy proved the presence of an Fe–N coordination bond between FePc and surface-bound pyridine. The resulting hybrid exhibited notably enhanced electrocatalytic NRR performance compared to FePc immobilized on CNTs based on π–π stacking interactions (FePc-CNT), resulting in doubled NH3 yield (21.7 μg mgcat –1 h–1) and Faradaic efficiency (22.2%). Theoretical calculations revealed that the axial coordination on FePc resulted in partial electron transfer from iron to pyridine, which efficiently suppresses the adsorption of H+ and improves the chemisorption of N2 at Fe sites. Meanwhile, the interfacial electron transfer was facilitated by pyridine as an electron transfer relay between FePc and CNTs. This work provides a unique strategy for the design of highly efficient NRR electrocatalysts at the molecular level.