More Like this

1. Laser induced graphene-based glucose biofuel cell

   https://doi.org/10.1109/SENSORS47087.2021.9639554  

   Hossain, Md Faruk ; Slaughter, Gymama ( October 2021 , 2021 IEEE Sensors)

   A glucose biofuel cell is presented using laser induced 3D graphene (LIG) substrate integrated with catalytic active nanomaterials for harnessing the biochemical energy of glucose. The LIG anode comprised glucose dehydrogenase immobilized on reduced graphene oxide and multiwalled carbon nanotubes (RGO/MWCNTs) nanocomposite for glucose oxidation. The LIG cathode is modified with RGO/MWCNTs and silver oxide (Ag 2 O) nanocomposites for the reduction of oxygen. The assembled biofuel cell exhibited a linear peak power response up to 18 mM glucose with sensitivity of 0.63 μW mM -1 cm −2 and exhibited good linearity (r 2 = 0.99). The glucose biofuel cell showed an open-circuit voltage of 0.365 V, a maximum power density of 11.3 μW cm −2 at a cell voltage of 0.25 V, and a short-circuit current density of 45.18 μA cm −2 when operating in 18 mM glucose. Cyclic voltammetry revealed the bioanode exhibited similar linearity for the detection of glucose. These results demonstrate that LIG based bioelectrodes offer great promise for diverse applications in the development of hybrid biofuel cell and biosensor technology. 

   more » « less
2. Electrocatalytic Conversion of Furanic Compounds for Production of Valuable Chemicals

   Li, Wenzhen ; Chadderdon, Xiaotong ; Chadderdon, David ; Liu, Hengzhou ( August 2021 , 72nd International Society of Electrochemistry Meeting)

   Biomass is abundant, inexpensive and renewable, therefore, it is highly expected to play a significant role in our future energy and chemical landscapes. The US DOE has identified furanic compounds (furfural and 5-(hydroxymethyl)furfural (HMF)) as the top platform building-block chemicals that can be readily derived from biomass sources [1]. Electrocatalytic conversion of these furanic compounds is an emerging route for the sustainable production of valuable chemicals [2, 3]. In my presentation, I will first present our recent mechanistic study of electrochemical reduction of furfural through a combination of voltammetry, preparative electrolysis, thiol-electrode modifications, and kinetic isotope studies [4]. It is demonstrated that two distinct mechanisms are operable on metallic Cu electrodes in acidic electrolytes: (i) electrocatalytic hydrogenation (ECH) and (ii) direct electroreduction. The contributions of each mechanism to the observed product distribution are clarified by evaluating the requirement for direct chemical interactions with the electrode surface and the role of adsorbed hydrogen. Further analysis reveals that hydrogenation and hydrogenolysis products are generated by parallel ECH pathways. Understanding the underlying mechanisms enables the manipulation of furfural reduction by rationally tuning the electrode potential, electrolyte pH, and furfural concentration to promote selective formation of important bio-based polymer precursors and fuels. Next, I will present electrocatalytic conversion of HMF to two biobased monomers in an H-type electrochemical cell [5]. HMF reduction (hydrogenation) to 2,5-bis(hydroxymethyl)furan (BHMF) was achieved under mild electrolyte conditions and ambient temperature using a Ag/C cathode. Meanwhile, HMF oxidation to 2,5-furandicarboxylic acid (FDCA) with ~100% efficiency was facilitated under the same conditions by a homogeneous nitroxyl radical redox mediator, together with an inexpensive carbon felt anode. The selectivity and efficiency for Ag-catalyzed BHMF formation were sensitive to cathode potential, owing to competition from HMF hydrodimerization reactions and water reduction (hydrogen evolution). Moreover, the carbon support of Ag/C was active for HMF reduction and contributed to undesired dimer/oligomer formation at strongly cathodic potentials. As a result, high BHMF selectivity and efficiency were only achieved within a narrow potential range near –1.3 V. Fortunately, the selectivity of redox-mediated HMF oxidation was insensitive to anode potential, thus allowing HMF hydrogenation and oxidation half reactions to be performed together in a single cathode-potential-controlled cell. Electrocatalytic HMF conversion in a paired cell achieved high molar yields of BHMF and FDCA, and nearly doubled electron efficiency compared to the unpaired cell. Finally, I will briefly introduce our recent work on the development of a three-electrode flow cell with an oxide-derived Ag (OD-Ag) cathode and catbon felt anode for paring elecatalytic oxidation and reduction of HMF. The flow cell has a remarkable cell voltage reduction from ~7.5 V to ~2.0 V by transferring the electrolysis from the H-type cell to the flow cell [6]. This represents a more than fourfold increase in the energy efficiency at the 10 mA operation. A combined faradaic efficiency of 163% was obtained to BHMF and FDCA. Alternatively, the anodic hydrogen oxidation reaction on platinum further reduced the cell voltage to only ~0.85 V at 10 mA operation. These paired processes have shown potential for integrating renewable electricity and carbon for distributed chemical manufacturing in the future. 

   more » « less
3. In Situ, Fast, High‐Temperature Synthesis of Nickel Nanoparticles in Reduced Graphene Oxide Matrix

   https://doi.org/10.1002/aenm.201601783  

   Li, Yiju ; Chen, Yanan ; Nie, Anmin ; Lu, Aijiang ; Jacob, Rohit Jiji ; Gao, Tingting ; Song, Jianwei ; Dai, Jiaqi ; Wan, Jiayu ; Pastel, Glenn ; et al ( January 2017 , Advanced Energy Materials)

   For the first time, a fast heating–cooling process is reported for the synthesis of carbon‐coated nickel (Ni) nanoparticles on a reduced graphene oxide (RGO) matrix (nano‐Ni@C/RGO) as a high‐performance H₂O₂fuel catalyst. The Joule heating temperature can reach up to ≈2400 K and the heating time can be less than 0.1 s. Ni microparticles with an average diameter of 2 µm can be directly converted into nanoparticles with an average diameter of 75 nm. The Ni nanoparticles embedded in RGO are evaluated for electro‐oxidation performance as a H₂O₂fuel in a direct peroxide–peroxide fuel cell, which exhibits an electro‐oxidation current density of 602 mA cm⁻²at 0.2 V (vs Ag/AgCl), ≈150 times higher than the original Ni microparticles embedded in the RGO matrix (micro‐Ni/RGO). The high‐temperature, fast Joule heating process also leads to a 4–5 nm conformal carbon coating on the surface of the Ni nanoparticles, which anchors them to the RGO nanosheets and leads to an excellent catalytic stability. The newly developed nano‐Ni@C/RGO composites by Joule heating hold great promise for a range of emerging energy applications, including the advanced anode materials of fuel cells.

    

   more » « less
4. A non-enzymatic glucose sensor based on a CoNi 2 Se 4 /rGO nanocomposite with ultrahigh sensitivity at low working potential

   https://doi.org/10.1039/c9tb00104b  

   Amin, Bahareh Golrokh ; Masud, Jahangir ; Nath, Manashi ( April 2019 , Journal of Materials Chemistry B)

   Uniform and porous CoNi 2 Se 4 was successfully synthesized by electrodeposition onto a composite electrode comprising reduced graphene oxide (rGO) anchored on a Ni foam substrate (prepared hydrothermally). This CoNi 2 Se 4 –rGO@NF composite electrode has been employed as an electrocatalyst for the direct oxidation of glucose, thereby acting as a high-performance non-enzymatic glucose sensor. Direct electrochemical measurement with the as-prepared electrode in 0.1 M NaOH revealed that the CoNi 2 Se 4 –rGO nanocomposite has excellent electrocatalytic activity towards glucose oxidation in an alkaline medium with a sensitivity of 18.89 mA mM −1 cm −2 and a wide linear response from 1 μM to 4.0 mM at a low applied potential of +0.35 V vs. Ag|AgCl. This study also highlights the effect of decreasing the anion electronegativity on enhancing the electrocatalytic efficiency by lowering the potential needed for glucose oxidation. The catalyst composite also exhibits high selectivity towards glucose oxidation in the presence of several interferents normally found in physiological blood samples. A low glucose detection limit of 0.65 μM and long-term stability along with a short response time of approximately 4 seconds highlights the promising performance of the CoNi 2 Se 4 –rGO@NF electrode for non-enzymatic glucose sensing with high precision and reliability. 

   more » « less
5. Electrocatalytic Hydrogenation of Furanic Compounds: From Mechanism Study to Paired Electrolyzer Design

   Li, Wenzhen ; Liu, Hengzhou ; Chadderdon, Xiaotong ; Chadderdon, David ; Lee, Ting-Han ; Cochran, Eric ( August 2021 , 262nd ACS National Meeting)

   Biomass is abundant, inexpensive and renewable, therefore, it is highly expected to play a significant role in our future energy and chemical landscapes. The US DOE has identified furanic compounds (furfural and 5-(hydroxymethyl)furfural (HMF)) as the top platform building-block chemicals that can be readily derived from biomass sources [1]. Electrocatalytic conversion of these furanic compounds is an emerging route for the sustainable production of valuable chemicals [2, 3]. In my presentation, I will first present our recent mechanistic study of electrocatlytic hydrogenation (ECH) of furfural through a combination of voltammetry, preparative electrolysis, thiol-electrode modifications, and kinetic isotope studies [4]. It is demonstrated that two distinct mechanisms are operable on metallic Cu electrodes in acidic electrolytes: (i) electrocatalytic hydrogenation (ECH) and (ii) direct electroreduction. The contributions of each mechanism to the observed product distribution are clarified by evaluating the requirement for direct chemical interactions with the electrode surface and the role of adsorbed hydrogen. Further analysis reveals that hydrogenation and hydrogenolysis products are generated by parallel ECH pathways. Understanding the underlying mechanisms enables the manipulation of furfural reduction by rationally tuning the electrode potential, electrolyte pH, and furfural concentration to promote selective formation of important bio-based polymer precursors and fuels We further studied the mechanisms on the Pb electrode, based on the potential regulated ECH and ER products. Isotopic incorporation studies and electrokinetics have confirmed ECH process to alcohol and alkyl product followed different pathways: alcohol was generated from Langmuir Hinshelwood step through surface-bound furfural and hydrogen, which is sensitive to surface structures. In contrast, alkyl product was formed through an Eley–Rideal step via surface-bound furfural and the inner-sphere protons. By modifying the electrode/electrolyte interface, we have elucidated H2O and H3O+ matters in forming alcohol and alkyl products, respectively. Dynamic oscillation studies and electron paramagnetic resonance (EPR) finally confirmed that the alcohol and dimer products shared the same intermediate. The dimer was formed through the intermediate desorption from the surface to form radicals and the self-coupling of two radicals at the bulk electrolyte. Next, I will present electrocatalytic conversion of HMF to two biobased monomers in an H-type electrochemical cell [5]. HMF reduction (hydrogenation) to 2,5-bis(hydroxymethyl)furan (BHMF) was achieved under mild electrolyte conditions and ambient temperature using a Ag/C cathode. Meanwhile, HMF oxidation to 2,5-furandicarboxylic acid (FDCA) with ~100% efficiency was facilitated under the same conditions by a homogeneous nitroxyl radical redox mediator. We recently developed a three-electrode flow cell with an oxide-derived Ag (OD-Ag) cathode and catbon felt anode for paring elecatalytic oxidation and reduction of HMF [6]. The flow cell has a remarkably low cell voltage: from ~7.5 V to ~2.0 V by transferring the electrolysis from the H-type cell to the flow cell. This represents a more than fourfold increase in the energy efficiency at the 10 mA operation. A combined faradaic efficiency of 163% was obtained to BHMF and FDCA. Alternatively, the anodic hydrogen oxidation reaction on platinum further reduced the cell voltage to only ~0.85 V at 10 mA operation. These paired processes have shown potential for integrating renewable electricity and carbon for distributed chemical manufacturing in the future. 

   more » « less