Lignosulfonate-Modified Electrode for Electrocatalytic Reduction of Acidic Nitrite

Lignin-Derived Quinone Redox Moieties for Bio-Based Supercapacitors

Because of their rapid charging and discharging, high power densities, and excellent cycling life stabilities, supercapacitors have great potential for use in electric vehicles, portable electronics, and for grid frequency modulation. The growing need for supercapacitors that are both efficient and ecologically friendly has generated curiosity in developing sustainable biomass-based electrode materials and electrolytes. Lignin, an aromatic polymer with remarkable electroactive redox characteristics and a large number of active functional groups, is one such candidate for use in renewable supercapacitors. Because its chemical structure features an abundance of quinone groups, lignin undergoes various surface redox processes, storing and releasing both electrons and protons. Accordingly, lignin and its derivatives have been tested as electroactive materials in supercapacitors. This review discusses recent examples of supercapacitors incorporating electrode materials and electrolytes derived from lignin, focusing on the pseudocapacitance provided by the quinone moieties, with the goal of encouraging the use of lignin as a raw material for high-value applications. Employing lignin and its derivatives as active materials in supercapacitor electrodes and as a redox additive in electrolytes has the potential to minimize environmental pollution and energy scarcity while also providing economic benefits.

Lignin biopolymer: the material of choice for advanced lithium-based batteries

Lignin, an aromatic polymer, offers interesting electroactive redox properties and abundant active functional groups. Due to its quinone functionality, it fulfils the requirement of erratic electrical energy storage by only providing adequate charge density. Research on the use of lignin as a renewable material in energy storage applications has been published in the form of reviews and scientific articles. Lignin has been used as a binder, polymer electrolyte and an electrode material, i.e. organic composite electrodes/hybrid lignin-polymer combination in different battery systems depending on the principal charge of quinone and hydroquinone. Furthermore, lignin-derived carbons have gained much popularity. The aim of this review is to depict the meticulous follow-ups of the vital challenges and progress linked to lignin usage in different lithium-based conventional and next-generation batteries as a valuable, ecological and low-cost material. The key factor of this new finding is to open a new path towards sustainable and renewable future lithium-based batteries for practical/industrial applications.

"Waste to Wealth": Lignin as a Renewable Building Block for Energy Harvesting/Storage and Environmental Remediation

Lignin is the second most earth-abundant biopolymer having aromatic unit structures, but it has received less attention than other natural biomaterials. Recent advances in the development of lignin-based materials, such as mesoporous carbon, flexible thin films, and fiber matrix, have found their way into applications to photovoltaic devices, energy-storage systems, mechanical energy harvesters, and catalytic components. In this Review, we summarize and suggest another dimension of lignin valorization as a building block for the synthesis of functional materials in the fields of energy and environmental applications. We cover lignin-based materials in the photovoltaic and artificial photosynthesis for solar energy conversion applications. The most recent technological evolution in lignin-based triboelectric nanogenerators is summarized from its fundamental properties to practical implementations. Lignin-derived catalysts for solar-to-heat conversion and oxygen reduction are discussed. For energy-storage applications, we describe the utilization of lignin-based materials in lithium-ion rechargeable batteries and supercapacitors (e.g., electrodes, binders, and separators). We also summarize the use of lignin-based materials as heavy-metal adsorbents for environmental remediation. This Review paves the way to future potentials and opportunities of lignin as a renewable material for energy and environmental applications.

Hydrogenation of α-Pinene over Platinum Nanoparticles Reduced and Stabilized by Sodium Lignosulfonate

A one-pot clean preparation procedure and catalytic performance of platinum nanoparticles (NPs) reduced and stabilized by sodium lignosulfonate in aqueous solution are reported. No other chemical reagents are needed during the metal reduction and stabilization step, thanks to the active participation of sodium lignosulfonate (SLS). UV-vis, Fourier transform infrared (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), 1H NMR, 195Pt NMR, and two-dimensional heteronuclear single-quantum coherence (2D HSQC) NMR studies were thoroughly performed to analyze the formation, particle size, and main lattice planes of NPs, the valence-state changes of the metal, and structural changes of SLS. An ecofriendly selective synthesis of cis-pinane from an abundant renewable natural resource, α-pinene, was developed in the presence of the prepared Pt NP aqueous system. Furthermore, this catalyst system was proved to show easy recovery and stable reusability by five-run tests. The synergistic effect of SLS reduction and stabilization not only avoided the introduction of conventional reducing agents and stabilizers but also made full use of the byproducts of the pulp and paper industry. This proved to be an environmentally friendly method for converting the natural resource α-pinene to cis-pinane.

25th anniversary article: organic photovoltaic modules and biopolymer supercapacitors for supply of renewable electricity: a perspective from Africa

The role of materials in civilization is well demonstrated over the centuries and millennia, as materials have come to serve as the classifier of stages of civilization. With the advent of materials science, this relation has become even more pronounced. The pivotal role of advanced materials in industrial economies has not yet been matched by the influence of advanced materials during the transition from agricultural to modern societies. The role of advanced materials in poverty eradication can be very large, in particular if new trajectories of social and economic development become possible. This is the topic of this essay, different in format from the traditional scientific review, as we try to encompass not only two infant technologies of solar energy conversion and storage by means of organic materials, but also the social conditions for introduction of the technologies. The development of organic-based photovoltaic energy conversion has been rapid, and promises to deliver new alternatives to well-established silicon photovoltaics. Our recent development of organic biopolymer composite electrodes opens avenues towards the use of renewable materials in the construction of wooden batteries or supercapacitors for charge storage. Combining these new elements may give different conditions for introduction of energy technology in areas now lacking electrical grids, but having sufficient solar energy inputs. These areas are found close to the equator, and include some of the poorest regions on earth.

Synthesis and Electroanalytical Performance of a Composite Material Based on Poly(3,4-ethylenedioxythiophene) Doped with Lignosulfonate

3,4-ethylenedioxythiophene (EDOT) was electropolymerized in the presence of sodium lignosulfonate (LS) at constant current density of 0.25 mA cm−2. As a result, a thin composite film consisting of poly(3,4-Ethylenedioxythiophene) and LS (PEDOT/LS) was deposited on the electrode surface. Unlike PEDOT, PEDOT/LS shows appreciable redox activity due to LS-derived quinone moieties with diffusion-like charge propagation across the film thickness. The film-modified gold electrodes can be used as voltammetric sensor of uric acid (UA) in the presence of ascorbic acid (AA). Interestingly, the UA response is catalysed by the presence of AA, and for high AA/UA concentration ratios more than 10-fold enhancement of the UA peak currents are apparent.

Lignosulfonate-modified electrodes: electrochemical properties and electrocatalysis of NADH oxidation

Lignosulfonic acid (LS1) and partially desulfonated lignosulfonic acid (LS2) were oxidatively deposited on a preactivated glassy carbon (GC) electrode, giving rise to redox active films showing three distinct redox couples at midpeak potentials (E degrees ') of 0.22, 0.44, and 0.53 V (vs Ag/AgCl in 0.1 M H(2)SO(4)). The redox activity was assigned to quinone moieties of different degrees of substitution, formed upon the oxidation of electroactive groups in the lignosulfonate structure. The most predominant couple (E degrees ' = 0.44 V) shifted negatively with pH at a rate of 59.5 mV per pH unit. In neutral electrolytes, the LS1- and LS2-modified electrodes behaved as anionic coatings, showing an increase in the charge transfer resistance (R(ct)) for the ferrocyanide/ferricyanide redox couple. The change in R(ct) was highly dependent on the LS sulfonation degree, and in comparison to an unmodified electrode it increased by ca. 490% for LS1-modified electrodes and by only 53% for LS2-modified electrodes. The LS-modified electrodes showed high electrocatalytic activity toward oxidation of reduced nicotinamide adenine dinucleotide (NADH). Electrocatalysis was studied in TRIS-HNO(3) buffers having pH of 5.0, 7.5, and 8.5 in the absence and presence of 20 mM Mg(2+), using the rotating disk electrode technique. Determined kinetic constants revealed that the impact of electrocatalysis depended strongly on the pH, the LS sulfonation degree, and the presence of bivalent metal ions. At fixed pH, the observed oxidation rate constant was lower for LS1-based electrodes than for LS2-based electrodes. On the other hand, the relative enhancement of this constant caused by the presence of Mg(2+) ions was much higher for LS1-based electrodes than for LS2-based electrodes. This phenomenon was explained by the participation of sulfonic groups in the formation of a ternary complex between quinone moiety, metal ions, and NADH. The values of other kinetic constants, including the Michaelis-Menten constant (K(M)), suggested that the formation of such a complex is preferred in alkaline pHs.