The d-band center and surface negative charge density generally determine the adsorption and activation of CO, thus serving as important descriptors of the catalytic activity toward CO hydrogenation. Herein, we engineered the d-band center and negative charge density of Rh-based catalysts by tuning their dimensions and introducing non-noble metals to form an alloy. During the hydrogenation of CO into methanol, the catalytic activity of RhW nanosheets was 5.9, 4.0, and 1.7 times as high as that of Rh nanoparticles, Rh nanosheets, and RhW nanoparticles, respectively. Mechanistic studies reveal that the remarkable activity of RhW nanosheets is owing to the integration of quantum confinement and alloy effect. Specifically, the quantum confinement in one dimension shifts up the d-band center of RhW nanosheets, strengthening the adsorption of CO. Moreover, the alloy effect not only promotes the activation of CO to form CO but also enhances the adsorption of intermediates to facilitate further hydrogenation of the intermediates into methanol.

Background The aim of this study was to evaluate the effectiveness and safety of different treatment strategies for endogenic caesarean scar pregnancy (CSP) patients. Methods According to Vial’s standard, we defined endogenic-type CSP as (1) the gestational sac growing towards the uterine cavity and (2) a greater than 0.3 cm thickness of myometrial tissue at the caesarean scar. A total of 447 endogenic CSP patients out of 527 patients from 4 medical centres in China were enrolled in this study. A total of 120 patients were treated with methotrexate (MTX) followed by surgery, 106 received ultrasound-guided curettage directly and 221 received curettage combined with hysteroscopy. The clinical information and clinical outcomes of these patients were reviewed. Successful treatment was defined as (1) no additional treatment needed, (2) no retained mass of conception and (3) serum β subunit of human chorionic gonadotropin (β-hCG) level returning to a normal level within 4 weeks. The success rate was analysed based on these factors. Result Among 447 patients, no significant difference was observed in baseline characteristics between groups except for foetal heartbeat. The success rate was significantly different (p<0.001) among the three groups. The highest success rate of 95.9% was noted in the hysteroscopy group, and the lowest success rate of 84.0% was noted in the curettage group. In addition, the MTX group reported the longest hospital stay and highest expenses, but the curettage group showed the shortest and lowest expenses, respectively. Nevertheless, no difference in blood loss was observed between the groups. Conclusion The combination of curettage and hysteroscopy represents the most effective strategy. Pretreatment with MTX did not result in better clinical outcomes. Ultrasound-guided curettage directly should not be considered a first-line treatment choice for endogenic CSP patients.

A new cesarean scar ectopic pregnancy clinical classification system based on anterior myometrial thickness and gestational sac diameter with recommended surgical strategy for each classification type resulted in high treatment success rates.