Volume 151, October 2019, Pages 160-174. 

Harsimranjit SinghShiqiang Zhuang, Benjamin Ingis, Bharath Babu Nunna, *Eon Soo Lee


This review focuses on the historic and recent progress of the stability of the carbon-based non-platinum-group metal (PGM) and metal-free catalysts for oxygen reduction reaction (ORR). It highlights the reported degradation mechanisms which are responsible for the instability issue. These mechanisms are (a) oxidative attack of the ORR intermediates, (b) demetalation of the metal-active site, (c) protonation followed by anionic adsorption, and (d) micropore flooding. For the metal-based catalysts, mechanisms (a) and (b) are the most commonly observed. From the review, it is known that the oxidative attack of ORR intermediates leads to the carbon oxidation, which can also result in the demetalation of the metal-active site. Additionally, the demetalation of the iron-based catalysts can also indirectly oxidize the carbon-support via Fenton reaction. The mechanisms (c) and (d) are sharply criticized. Finally, for the metal-free carbon-based catalysts, there is only a limited research available on the stability of these catalysts. Among the reported study, the mechanisms (a) and (c) can be responsible for the degradation of these catalysts. Therefore, it is recommended that more study should be focused on investigating the degradation parameters and mechanisms for metal-free catalysts.

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Thermal Stability and Potential Cycling Durability of Nitrogen-Doped Graphene Modified by Metal-Organic Framework for Oxygen Reduction Reactions

Harsimranjit Singh, Shiqiang Zhuang , Bharath Babu Nunna and Eon Soo Lee *

Catalysts 20188(12), 607;


Sensitivity Study of Cancer Antigens (CA-125) Detection Using Interdigitated Electrodes Under Microfluidic Flow Condition

Bharath Babu Nunna1 & Debdyuti Mandal1 & Joo Un Lee2 & Shiqiang Zhuang1 & Eon Soo Lee1

BioNanoScience (2019)

# Springer Science+Business Media, LLC, part of Springer Nature 2019


 Bharath Babu Nunna1, Debdyuti Mandal1, Joo Un Lee2, Harsimranjit Singh1, Shiqiang Zhuang1, Durgamadhab Misra3, Md Nasir Uddin Bhuyian3 and Eon Soo Lee1*

Nunna et al. Nano Convergence (2019)


  • Zhuang, S., Singh, H., Nunna, B.B., Mandal, D., Bosoboinik, J.A., Lee, E.S.* (2018).
  • Nitrogen-doped graphene-based catalyst with metal-reduced organic framework: Chemical analysis and structure control,
  • Carbon, Volume 139, Pages 933-944.

Metal-organic framework-modified nitrogen-doped graphene oxygen reduction reaction catalyst synthesized by nanoscale high-energy wet ball-milling structural and electrochemical characterization


It is very crucial to diagnose cancer biomarkers at the early stages. The early detection of the disease can enhance the preventive measures, increase curability of the disease, reduce health care costs, and finally, improve the quality of life for patients. This paper explains innovation in the field of complex diseases diagnosis, by detecting the disease antigen using the interdigitated gold electrode circuit incorporated with gold nanoparticles under a controlled self-driven flow condition in a microfluidic based biosensor.

The integrated module of microfluidics with the biosensor is of great research interest with the increasing trend of lab-on-the chip and point-of-care devices. Though there are numerous studies performed on associating the microfluidics to the biosensing mechanisms, the study of the sensitivity variation due to microfluidic flow is very much limited. In this paper, a study of the sensitivity variation while detecting the CA-125 antigen using interdigitated electrodes, ‘with’ and ‘without’ microfluidic flow of CA-125 antigens was performed.

The detection and determination of the cancer biomarkers is very crucial to diagnose at the early stages. We implement to design the biosensor which can improve the detection by reducing the process time, cost and space. The research approach mainly is focused on developing a surface modification protocol for better sensitivity under the shear flow rate conditions using carbon nanotubes (CNTs).

Platinum group metals (PGM), such as platinum (Pt) or ruthenium (Ru), are the most common catalyst materials for the oxygen reduction reaction (ORR) because of their excellent catalytic performance. However, the high raw material cost of PGM catalysts has become a significant issue. Currently, the nitrogen-doped graphene (N-G) catalyst emerges as one of the promising non-PGM catalysts with the advantages of low cost and high ORR catalytic performance to replace expensive PGM catalysts in electrochemical systems.

Nitrogen-doped graphene (N-G) catalyst emerges as one of the promising non-platinum group metal (non-PGM) catalysts with the advantages of low cost, high oxygen reduction reaction (ORR) activity, stability, and selectivity to replace expensive PGM catalysts in electrochemical systems. In this research, nanoscale high energy wet (NHEW) ball milling is first investigated for the synthesis of N-G catalysts to make conventional problems such as sintering or localized overheating issues negligible.

Most of the cancers are curable if they are detected at early stages. The early stage detection of cancers can significantly improve the patient treatment outcomes and thus helps to decrease the. To achieve the early detection of specific cancer, the biochip is incorporated with an innovative sensing mechanism and surface treated microchannels. The sensing mechanism employed in the Point of Care (POC) biochip is designed to be highly specific and sensitive.

Metal-organic frameworks (MOFs), which have advantages such as large surface area and high porosity, are recently investigated as a component of electrochemical catalysts to enhance the catalytic performance. But the influences of MOFs on the properties of catalysts such as surface structure, local structure of active sites, catalytic activity, and selectivity are still under investigation.

Platinum group metal-based (PGM) catalysts are widely applied in many electrochemical systems such as fuel cells or metalair batteries because of their excellent catalytic performance. But the high raw material cost of PGM catalysts has become a significant issue. In recent years, huge efforts have been made to reduce the material cost of electrochemical systems by developing non-PGM catalysts, and as one of the promising non-PGM catalysts, nitrogen-doped graphene (N-G) has emerged. In this research, nanoscale high-energy wet ball milling methodology was investigated as an effective synthesis method for N-G catalysts by using graphene oxide and melamine as raw materials. The main purpose is to study reaction mechanism of the synthesis process and the physical, chemical, and electrochemical properties of N-G catalysts generated by this mechanochemical approach.

An important function of the gas delivery channels in PEM fuel cells is the evacuation of water at the cathode. The resulting two-phase flow impedes reactant transport and causes parasitic losses. There is a need for research on two-phase flow in channels in which the phase fraction varies along the flow direction as in operating fuel cells. This work studies two-phase flow in 60cm long channels with distributed water injection through a porous GDL wall to examine the physics of flows relevant to fuel cells.

Jae-Young Lee, Jiyong Joo, Jae Kwang Lee, Sunghyun Uhm, Eon Soo Lee, Jae Hyuk Jang, Nam-Ki Kim, Yong-Chul Lee, Jaeyoung Lee

Korean J. Chem. Eng. 27(3), 843-847 (2010)

DOI: 10.1007/s11814-010-0141-7

Jiyong Joo, Jae Kwang Lee, Y. Kwon, C. R. Jung, Eon Soo Lee, Jae Hyuk Jang,H. J. Lee, Sunghyun Uhm, Jaeyoung Lee

Fuel Cells (2009)

DOI: 10.1002/fuce.200900026

Jongpil Choi, Eon-Soo Lee, Jae-Huk Jang, Young Ho Seo and Byeonghee Kim

World Academy of Science, Engineering and Technology (2009)

Vol:32 2009-08-20

Polymer electrolyte membrane (PEM) fuel cells incorporating microchannels (D < 500μm) can benefit from improved fuel delivery and convective cooling. However, this requires a better understanding of two-phase microchannel transport phenomena, particularly liquid–gas interactions and liquid clogging in cathode air-delivery channels. This paper develops optical fluorescence imaging of water films in hydrophilic channels with varying air velocity and water injection rate. Micromachined silicon test structures with optical access and ...

Microchannels (0.05–1 mm) improve gas routing in proton exchange membrane fuel cells, but add to the complexities of water management. This work microfabricates experimental structures with distributed water injection as well as with heating and temperature sensing capabilities to study water formation and transport. The samples feature optical access to allow visualization and distributed thermometry for investigation of two-phase flow transport phenomena in the microchannels. The temperature evolution along the channel is observed that the temperature downstream of the distributed water injection decreases as the pressure drop increases.

Industrial trends are presenting major challenges and opportunities for research on two-phase flows in microchannels. Semiconductor companies are developing 3D circuits for which multilevel microfluidic cooling is important. Gas delivery microchannels are promising for PEM fuel cells in portable electronics. However, data and modeling are needed for flow regime stability, liquid entrainment/clogging, and bubble inception/departure in complex 2D and 3D geometries. This paper provides an overview of the Stanford two-phase ...