Jianan Li

Bio: Jianan Li is an academic researcher from East China University of Science and Technology. The author has contributed to research in topics: Radical & Urea. The author has co-authored 4 publications.

Deciphering and Suppressing Over-Oxidized Nitrogen in Nickel-Catalyzed Urea Electrolysis

Abstract: Urea electrolysis is a prospective technology for simultaneous H2 production and nitrogen suppression in the process of water being used for energy production. Its sustainability is currently founded on innocuous N2 products; however, we discovered that prevalent nickel-based catalysts could generally over-oxidize urea into NO2- products with ≈80 % Faradaic efficiencies, posing potential secondary hazards to the environment. Trace amounts of over-oxidized NO3- and N2 O were also detected. Using 15 N isotopes and urea analogues, we derived a nitrogen-fate network involving a NO2- -formation pathway via OH- -assisted C-N cleavage and two N2 -formation pathways via intra- and intermolecular coupling. DFT calculations confirmed that C-N cleavage is energetically more favorable. Inspired by the mechanism, a polyaniline-coating strategy was developed to locally enrich urea for increasing N2 production by a factor of two. These findings provide complementary insights into the nitrogen fate in water-energy nexus systems.

Catalyst Design and Progresses for Urea Oxidation Electrolysis in Alkaline Media

Abstract: Urea, as a significant molecule in biology, chemistry and agriculture, is extensively present both in industrial production and daily life However, its excessively releasing into water and soil could bring about a serious threat to the environment and ecology due to the potential eutrophication Considering the potential hydrogen content in urea, urea-rich wastewater is also regarded as a strategic energy storage resource Among all technologies, the electrochemical treatment of urea wastewater behaves superior advantages both on environment protection and energy recovery, causing tremendous attention in recent years Herein, this review summarized electrochemical methods for urea conversions for pollutant control and energy harvesting As the kernel role in the electrochemical systems, the latest development of advanced electrodes is presented with the basic design principles described The relationships between the electrocatalysts and their urea oxidation performance have been discussed thoroughly Additionally, recent advances about novel applications for energy production and resource recovery are also displayed Finally, the prospects and challenges are still to be addressed, orienting a clear direction for the electrochemical hydrogen harvesting from urea-containing wastewater in the future

Medicament for in-situ chemical oxidation remediation of soil or underground water, and using method thereof

Abstract: The invention provides a medicament for in-situ chemical oxidation remediation of soil and underground water, and a using method thereof. The medicament comprises: 1) an enzyme preparation or a mimicenzyme preparation; and 2) an oxidizing agent which can be at least used for oxidizing an electron acceptor of a polluted substrate together with an enzyme preparation or a mimic enzyme preparation, wherein the adding mass concentration ratio of the oxidizing agent to the enzyme preparation is 1:(0.1 to 1 * 10 ), and the molar concentration ratio of the oxidizing agent to the enzyme preparationis 1: (0.001 to 1 * 10 ). The using method of the medicament comprises the following steps: mixing the enzyme preparation or the mimic enzyme preparation with the oxidizing agent in proportion, andinjecting the obtained mixture into polluted soil underground water; or firstly injecting the enzyme preparation or the mimic enzyme preparation into the ground, and then injecting the oxidizing agent; or firstly injecting the oxidizing agent into the polluted soil underground water, and then injecting the enzyme preparation or the mimic enzyme preparation. The medicament does not need an iron-containing activator, has mild use conditions, can efficiently remove underground pollutants, does not cause secondary pollution, and has small disturbance to the ground or underground ecological environment.

Coupling-Promoted Oxidative Degradation of Organic Micropollutants by Iron Oxychloride (FeOCl) with Dual Active Sites

Abstract: Heterogeneous Fenton has emerged as a profitable solution for contaminant removal via advanced oxidation processes (AOPs). Besides the dominant hydroxyl radicals (HO•), some weaker oxidants, such as ferryl-oxo species (Fe(IV)=O) species, can also be produced during the surface H2O2 activation, but its function is not well understood. In this study, we developed a vanadium-etched iron oxychloride (V-FeOCl) catalyst that simultaneously incorporates Fenton-like sites and peroxidase-like (Fe(IV)=O) sites. The derived V-FeOCl material showed 2.8-5.4 times enhancement of the pseudo-first-order rate constant for various recalcitrant organic micropollutants. Most importantly, the activity demonstrated an intriguing induction period for the TOC removal as well as a rocketed kinetics after the induction. This induction period was further attributed to the oxidative coupling of the organic monomers, as revealed by the identification of dimers using UPLC-MS. The coupling intermediates were demonstrated to be more susceptible to HO• radical attack via the high-throughput prediction of the HO• radical rate constants of 94 possible coupling intermediates using machine learning. These findings clarified the key role of Fe(IV)=O in the HO•-based oxidation process and points to a novel coupling-enhanced degradation pathway, which could potentially pave a new avenue of oxidative transformations for catalytic and environmental applications.

A review of Ni based powder catalyst for urea oxidation in assisting water splitting reaction

Abstract: Water splitting has been regarded as a sustainable and environmentally-friendly technique to realize green hydrogen generation, while more energy is consumed due to the high overpotentials required for the anode oxygen evolution reaction. Urea electrooxidation, an ideal substitute, is thus received increasing attention in assisting water-splitting reactions. Note that highly efficient catalysts are still required to drive urea oxidation, and the facile generation of high valence state species is significant in the reaction based on the electrochemical-chemical mechanisms. The high cost and rareness make the noble metal catalysts impossible for further consideration in large-scale application. Ni-based catalysts are very promising due to their cheap price, facile structure tuning, good compatibility, and easy active phase formation. In the light of the significant advances made recently, herein, we reviewed the recent advances of Ni-based powder catalysts for urea oxidation in assisting water-splitting reaction. The fundamental of urea oxidation is firstly presented to clarify the mechanism of urea-assisted water splitting, and then the prevailing evaluation indicators are briefly expressed based on the electrochemical measurements. The catalyst design principle including synergistic effect, electronic effect, defect construction and surface reconstruction as well as the main fabrication approaches are presented and the advances of various Ni-based powder catalysts for urea assisted water splitting are summarized and discussed. The problems and challenges are also concluded for the Ni-based powder catalysts fabrication, the performance evaluation, and their application. Considering the key influencing factors for catalytic process and their application, attention should be given to structure−property relationship deciphering, novel Ni-based powder catalysts development and their construction in the real device; specifically, the effort should be directed to the Ni-based powder catalyst with multi-functions to simultaneously promote the fundamental steps and high anti-corrosion ability by revealing the local structure reconstruction as well as the integration in the practical application. We believe the current summarization will be instructive and helpful for the Ni-based powder catalysts development and understanding their catalytic action for urea-assisted hydrogen generation via water splitting technique. Advances and challenges of Ni based powder catalyst were reviewed for urea oxidation in assisting water-splitting reaction.

Regulating the tip effect on single-atom and cluster catalysts: forming reversible oxygen species with high efficiency in chlorine evolution reaction.

Abstract: Chlorine evolution reaction has been applied in the production since a century ago. After times of evolution, it has been widely realized by the electrocatalytic process on anode nowadays. However, the anode applied in production contains a large amount of precious metal, increasing the cost. It is thus an opportunity to apply sub-nano catalysts in this field. By regulating the tip effect (TE) of the catalyst, it was discovered that the oxidized sub-nano iridium clusters supported by titanium carbide exhibit much higher efficiency than the single-atom one, which demonstrates the significance of modifying the electronic interaction. Moreover, it exhibits a ~20% decrease of the electricity, ~98% selectivity towards chlorine evolution reaction, and high durability of over 350 h. Therefore, this cluster catalyst performs great potential in applying in the practical production and the comprehension of the tip effect on different types of catalysts is also pushed to a higher level.

Strategies for Designing More Efficient Electrocatalysts towards Urea Oxidation Reaction

Abstract: Urea oxidation reaction (UOR) is a pivotal half-reaction for urea-assisted water splitting to produce hydrogen, direct urea fuel cells and electrochemical degradation of urea-containing wastewater. However, the intrinsic sluggish kinetics...

A review of hetero-structured Ni-based active catalysts for urea electrolysis

Abstract: Urea electrooxidation has received considerable attention because of its tremendous practical application in environmental protection and energy regeneration. As an electrochemical reaction, the catalytic performance of urea oxidation is highly...

Identification and manipulation of dynamic active site deficiency-induced competing reactions in electrocatalytic oxidation processes

Abstract: A detrimental competition between the urea oxidation reaction (UOR) and oxygen evolution reaction is identified. Strategies are proposed to alleviate such competition and boost the performance of the UOR and other organic compound oxidation reactions.