Dan Ren | EPFL Graph Search

Dan Ren studied Materials Science and Engineering in the Shanghai Jiao Tong University from 2009-2013. He then continued his study as a graduate student in the National University of Singapore with Prof. Jason Boon Siang Yeo and earned his Ph.D. degree in Chemistry in 2017. During his PhD, he developed Cu-based nanostructures and bimetallic systems for efficient and selective electrochemical reduction of carbon dioxide to multi-carbon products. He also developed in situ tools, especially in situ Raman spectroscopy, for probing electrocatalytic surface during carbon dioxide reduction and revealed the nature of active sites as well as the adsorbed intermediates. In early 2018, he moved to Switzerland and joined LPI as a postdoc. After working with Prof. Michael Graetzel for half a year, he was promoted to group leader and continued leading the solar fuel research subgroup since then. He is now working on electrocatalytic carbon dioxide reduction, operando Raman spectroscopy and system engineering for artificial photosynthesis. He has authored/co-authored >30 publications in prestigious academic journals and presented his work in >10 international conferences. These work have garnered >2000 citations and 6 of them are ESI highly cited papers (top 1% in the discipline of Chemistry). Together with Prof. Graetzel, he has successfully secured several grants both at national and international levels, including 'Solar-Bio Fuels' from Gebert Rüf Stiftung, 'SUN2CHEM' from EU H2020, '112CO2' from EU H2020, 'METHASOL' from EU H2020 and a collaboration grant from Saudi Arabia.

Exfoliated 2D Layered and Nonlayered Metal Phosphorous Trichalcogenides Nanosheets as Promising Electrocatalysts for CO2 Reduction

Michael Graetzel, Yelin Hu, Yunfei Jiao, Dan Ren, Chen Shen, Bing Wu, Hong Zhang

Two-dimensional (2D) materials catalysts provide an atomic-scale view on a fascinating arena for understanding the mechanism of electrocatalytic carbon dioxide reduction (CO2 ECR). Here, we successfully exfoliated both layered and nonlayered ultra-thin metal phosphorous trichalcogenides (MPCh(3)) nanosheets via wet grinding exfoliation (WGE), and systematically investigated the mechanism of MPCh(3) as catalysts for CO2 ECR. Unlike the layered CoPS3 and NiPS3 nanosheets, the active Sn atoms tend to be exposed on the surfaces of nonlayered SnPS3 nanosheets. Correspondingly, the nonlayered SnPS3 nanosheets exhibit clearly improved catalytic activity, showing formic acid selectivity up to 31.6 % with -7.51 mA cm(-2) at -0.65 V vs. RHE. The enhanced catalytic performance can be attributed to the formation of HCOO* via the first proton-electron pair addition on the SnPS3 surface. These results provide a new avenue to understand the novel CO2 ECR mechanism of Sn-based and MPCh(3)-based catalysts.

WILEY-V C H VERLAG GMBH2023

A universal co-solvent dilution strategy enables facile and cost-effective fabrication of perovskite photovoltaics

Paramvir Ahlawat, Masaud Hassan S Almalki, Viacheslav Bolnykh, Ulf Anders Hagfeldt, Anurag Krishna, Linfeng Pan, Dan Ren, Ursula Röthlisberger, Sandy Sanchez Alonso, Tzu-Sen Su, Narges Yaghoobi Nia, Shaik Mohammed Zakeeruddin, Hong Zhang

Cost management and toxic waste generation are two key issues that must be addressed before the commercialization of perovskite optoelectronic devices. We report a ground-breaking strategy for eco-friendly and cost-effective fabrication of highly efficient perovskitesolar cells. This strategy involves the usage of a high volatility co-solvent, which dilutesperovskite precursors to a lower concentration (1.4 M) solution. More than 70% of toxicwaste and material cost can be reduced. Mechanistic insights reveal ultra-rapid evaporationof the co-solvent together with beneficial alteration of the precursor colloidal chemistryupon dilution with co-solvent, which in-situ studies and theoretical simulations confirm.The co-solvent tuned precursor colloidal properties also contribute to the enhancement ofthe stability of precursor solution, which extends its processing window thus minimizing thewaste. This strategy is universally successful across different perovskite compositions, andscales from small devices to large-scale modules using industrial spin-coating, potentiallyeasing the lab-to-fab translation of perovskite technologies.

2022

Regulated CO adsorption by the electrode with OH− repulsive property for enhancing C–C coupling

Jing Gao, Michael Graetzel, Jingshan Luo, Dan Ren, Mingkui Wang, Xiaoyu Zhang, Qixing Zhang

Electrochemical CO2 reduction driven by renewable electricity is one of the promising strategies to store sustainable energy as fuels. However, the selectivity of value-added multi-carbon products remains poor for further application of this process. Here, we regulate CO adsorption by forming a Nafion layer on the copper (Cu) electrode that is repulsive to OH−, contributing to enhanced selectivity of CO2 reduction to C2+ products with the suppression of C1 products. The operando Raman spectroscopy indicates that the local OH− would adsorb on part of active sites and decrease the adsorption of CO. Therefore, the electrode with repulsive to OH− can adjust the concentration of OH−, leading to the increased adsorption of CO and enhanced C–C coupling. This work shows that electrode design could be an effective strategy for improving the selectivity of CO2 reduction to multi-carbon products.

2022