Oxidative Degradation Of Organic Pollutants Research Articles

Reinforcing 2D Single-Crystal Bi2O2CO3 with Additional Interlayer Carbonates by CO2-Assisted Solid-to-Solid Phase Transition.

A facile gaseous CO2 mediated solid-to-solid transformation principle is adopted to insert additional CO3 2- anions into the thin single-crystal nanosheets of Bi2O2CO3, which is built of periodic arrays of intrinsic CO3 2- anions and (Bi2O2)2+ layers. The additional CO3 2- anions create abundant defects. The Bi2O2CO3 nanosheets with rich interlayer CO3 2- exhibit superior electronic properties and charge transfer kinetics than the pristine single-crystal 2D Bi2O2CO3 and display enhanced catalytic activity in photocatalytic CO2 reduction reaction and the photocatalytic oxidative degradation of organic pollutants. This work thus illustrates interlayer engineering as a flexible means to build layered 2D materials with excellent properties.

Enhancing O2 adsorption and activation over porous S-doped g-C3N4 rod toward efficient photocatalytic rhodamine-B degradation

Photocatalytic oxygen molecular (O2) activation to generate reactive oxygen species (ROS) is a promising strategy for the oxidative degradation of organic pollutants. Herein, a porous S-doped g-C3N4 rod (S-g-CN-rod) was synthesized and applied to photocatalytic superoxide radicals (·O2-) evolution and rhodamine-B (RhB) degradation. The morphological, structural, and optical properties of all samples were investigated. DFT calculation demonstrated that the carbon site adjacent to S was energetically favorable for O2 adsorption, which was conducive to ·O2- evolution. The porous S-g-CN-rod exhibited an excellent photocatalytic ·O2- evolution rate of 268.2 μmol L−1 h−1, which was the main active species to degrade RhB. Conceivably, the porous S-g-CN-rod demonstrated exceptionally high efficiency of photocatalytic RhB degradation and achieved almost complete disposal of RhB (99.7 %) in only 30 min, which was higher than most reported photocatalysts. The experimental results and theoretical calculations demonstrated that the preeminent photocatalytic activities were ascribed to enhanced light-harvesting, improved migration and separation of photo-induced electrons, and the superior O2 adsorption and activation induced by S doping.

Ball-milled layer double hydroxide as persulfate activator for efficient degradation of organic: Alkaline sites-triggered non-radical mechanism

Considerable efforts have been put into enhancing the activation performance of peroxydisulfate (PDS) by catalysts toward oxidative degradation of organic pollutants, while the oxidative selectivity is somehow overlooked. Here, we reported an enhanced non-radical oxidation pathway of PDS, activated by ball-milled Mg/Al-layered double hydroxide (BM-LDH), to reconcile the selectivity and reactivity. EPR and quenching experiments suggested that 1O2 dominated the oxidative pathway for phenol degradation without generating carcinogenic halide by-products. Multiple interfacial characterizations and density functional theory (DFT) calculations revealed that BM-LDH played dual roles in PDS activation: (1) the interlaminar BM-LDH allowed PDS intercalation to form complexed PDS, resulting in decreases in the activation barrier of PDS; (2) abundant terminal hydroxyls in the layers of BM-LDH acted as alkaline-activation sites that can efficiently activate PDS to generate 1O2 toward phenol degradation. Ball-milling treatment of LDH refined the structural hierarchy of LDH to create pore volumes, which greatly enhanced the diffusion of phenol to the intercalated PDS, resulting in more than twice the reaction rate for phenol degradation. This study provided a promising approach to simultaneously control over the reactivity and selectivity toward PDS activation that are critical for the degradation of organic pollutants particularly in drinking water treatment.

Photo‐Assisted Fenton Reaction for the Oxidative Degradation of Organic Pollutants in Water Using a Layered Double Hydroxide of Iron Ion

AbstractThe Fenton reaction is widely known as a promising method for treating organic pollutants. We investigated the photo‐assisted oxidative degradation of pollutants using various layered double hydroxides (LDHs) to develop heterogeneous Fenton catalyst capable of mineralizing organic pollutants. A LDH composed of Fe2+ and Al3+ (Fe2+Al3+‐LDH) under the irradiation of visible‐light (λ>420 nm) resulted in 2.5 times higher performance for the oxidative degradation (mineralization) of phenol as a model compound of organic pollutants compared with that without light irradiation. The ratio of Fe2+/Fe3+ on the surface of the Fe2+Al3+‐LDH after the reaction under the irradiation of visible‐light increased significantly compared with that without light irradiation. These indicated that the Fenton‐catalytic‐cycle was improved by reducing the Fe3+ generated after the Fenton reaction to the Fe2+ species by the photo‐assisted effects of the Fe2+Al3+‐LDH.

Degradation of oxytetracycline by iron-manganese modified industrial lignin-based biochar activated peroxy-disulfate: Pathway and mechanistic analysis

In this study, high-performance Fe-Mn-modified industrial lignin-based biochar (FMBC) was successfully prepared to facilitate the efficient degradation of oxytetracycline by its driven sulfate radical-based advanced oxidation process with 90% degradation within 30 min. The results showed that oxygenated functional groups (e. g. hydroxyl, carbonyl, etc.) in industrial lignin-based biochar, the synergistic effect of transition metals Fe and Mn, and defective structures were the active sites for activation of peroxy-disulfate. SO4·− produced during the degradation process assumed a key function. Significantly, 38 intermediates were innovatively proposed for the first time in the system, and oxytetracycline was degraded in 7 ways, including deamidation, demethylation, hydroxylation, secondary alcohol oxidation, ring opening, dehydration, and carbonylation. A new perspective on the application of industrial lignin in the advanced oxidative degradation of organic pollutants was provided by this study.

Tailoring crystal facet microenvironments for simultaneous electrochemical ozone and hydrogen peroxide production

AbstractDeveloping a bifunctional electrocatalyst that can effectively produce O3 and H2O2 is significant for the electrochemical synthesis of O3 and H2O2 for the synergistic oxidative degradation of organic pollutants. In this study, SnO with various exposed facets was synthesized by tailoring the crystal facet microenvironment for oxygen intermediates adsorption for electrochemical ozone production (EOP) and two‐electron oxygen reduction reaction (2e− ORR). The Faraday efficiency of SnO‐1 with a high (110) facet ratio for O3 was 22.0%, while SnO‐4 with a high (002) facet ratio achieved a selectivity of 93.6% for H2O2. The theoretical calculation indicates that their excellent performances originated from the strong adsorption of the (110) facet on O* and O2* and the suitable adsorption and desorption strength of the (002) facet on OOH*, respectively. This study provides an attractive strategy for the development of a bifunctional electrocatalyst for advanced electrochemical oxidation by tailoring the crystal facet microenvironment.

Synergistic enhancement of photocatalytic molecular oxygen activation by nitrogen defect and interfacial photoelectron transfer over Z-scheme α-Fe2O3/g-C3N4 heterojunction

Photoinduced molecular oxygen activation offers a promising strategy for oxidative degradation of organic pollutants, but the critical step of oriented electron delivery from the active sites into the stable O2 molecules presents a considerable challenge. Herein, we report the construction of a direct Z-scheme heterojunction with abundant nitrogen defects (α-Fe2O3/g-C3N4) for powering molecular oxygen activation by steering a specific migration route. This specific interfacial photoelectron transfer pathway showcases the establishment of an effective sequential photoelectron transfer channels between α-Fe2O3 and g-C3N4. The nitrogen defects on the g-C3N4 surface can not only serve as the oxygen adsorption sites, but also can act as the terminal electron sink to donate photoexcited high-energy electrons to the adsorbed O2. Therefore, the optimized α-Fe2O3/g-C3N4 exhibits greatly enhanced catalytic performance for molecular oxygen activation, and the degradation rate constant of tetracycline is 4.7 and 12 times higher than g-C3N4 and α-Fe2O3, respectively.

Engineered tourmaline/g-C3N4 composites for photocatalytic Fenton-like oxidation: Synergy of spontaneous interface polarization and surface iron circulations induced by minerals

The peroxymonosulfate/peroxydisulfate (PMS/PDS) activation induced by photocatalytic reduction reaction is an economical and green means for oxidative degradation of organic pollutants in water. However, its efficiency is largely limited by the rapid recombination of photogenerated electron-holes. Herein, we report a graphitic carbon nitride (g-C3N4)-based photocatalytic persulfate activation system fine-tuned by a natural polarized Fe-containing mineral, tourmaline. The tourmaline/g-C3N4 composite photocatalyst was prepared to activate PMS for efficient carbamazepine (CBZ) degradation. In this system, the electrons and holes were produced by tourmaline/g-C3N4 composites under light excitation. Subsequently, PMS was activated by photogenerated electrons from g-C3N4 and Fe2+ on the surface of tourmaline to generate SO4•−, where partial SO4•− further reacted with H2O/OH– to produce •OH. Finally, the CBZ was oxidized by SO4•−, •OH and photo-induced holes. Under optimal conditions, with the presence of PMS, the degradation rate of CBZ conducted by tourmaline/g-C3N4 is 6.2 and 7.7 times of pristine g-C3N4 and tourmaline. It is revealed that the polarization electric field of tourmaline not only boosted the separation and migration of electron-hole of g-C3N4, but also optimized the electronic structure of g-C3N4 for intensified light absorption and improved reduction ability. Moreover, the Fe2+/Fe3+ cycle of tourmaline also facilitated the utilization of photogenerated electrons from g-C3N4 for PMS activation reactions. This study has innovatively constructed a photocatalytic PMS activation system enhanced by introducing natural Fe-containing polarized minerals, providing a new strategy for sustainable and low-cost advanced oxidation processes for water treatment.

Fenton-like Cerium Metal–Organic Frameworks (Ce-MOFs) for Catalytic Oxidation of Olefins, Alcohol, and Dyes Degradation

AbstractA metal–organic framework (MOF) of cerium (Ce) ions and 4,4′,4′′-nitrilotribenzoic acid linker was synthesized via a hydrothermal method. Ce-MOF consists of a Lewis acid moiety, i.e. Ce3+ and triphenylamine cores. It showed Fenton-like properties with excellent catalytic oxidation activity for olefins, primary/secondary alcohols, and water pollutants e.g., organic dyes. It displayed high oxidation conversion of cinnamyl alcohol and styrene of 100% and 53%, respectively. It offered good selectivity towards styrene oxide and benzaldehyde (i.e. 75% and 100%, respectively). It was applied for the oxidative degradation of dyes e.g. rhodamine B (RhB), methyl blue (MeB), Congo red (CR), and direct blue (DB) using hydrogen peroxide (H2O2) as an oxidant. It exhibited high efficiency in the oxidative degradation of these water pollutants. The mechanistic study of oxidation involves the formation of radical hydroxyl (•OH) species. This study revealed the possibility of enhancing the oxidative catalytic performance, including oxidative degradation of organic pollutants, by employing advanced oxidation processes (AOPs) using Ce-MOF. The catalyst is recyclable five times without significantly decreasing of the material’s catalytic performance.

Electrochemical-enhanced Fe3O4/biochar activates peroxymonosulfate (E/nano-Fe3O4/BC/PMS) for degradation of oxytetracycline

To find cost-effective and environmentally friendly free radical activators to stimulate peroxymonosulfate (PMS) oxidative degradation of organic pollutants, nano-Fe3O4/biochar (BC) composites were prepared and characterized in this work to examine their effectiveness in stimulating PMS oxidative degradation of Oxytetracycline (OTC) in water enhanced with electrochemical degradation. When the mass ratio of nano-Fe3O4 to BC is 1:1, the catalyst nano-Fe3O4/BC exhibits the most obvious degradation effect on OTC. After 4 h of degradation, the OTC concentrations were reduced from 20 to 2.65 mg L−1, while treated with a single nano-Fe3O4 and a single BC are reduced by only 67.7% and 61.8%. Anions HCO3− and H2PO4− significantly inhibit OTC degradation, and HCO3− has a stronger inhibitory effect than H2PO4−, while Cl− and NO3− can promote OTC degradation. Quenching test and electron spin paramagnetic resonance (EPR) detection showed that singlet oxygen (1O2) was the main active species in the degradation process, followed by hydroxyl radical (·OH). When reused for the third time, the removal rate of OTC by nano-Fe3O4/BC composites with mass ratios of 1:4, 1:2 and 1:1 was still more than 70%. Therefore, the nano-Fe3O4/BC composite is a promising PMS activator, which can realize the rapid oxidative degradation of OTC.

Three-dimensional functional carbon nanotube architecture as a highly efficient and active indirect catalyst for degradation of 4-chlorophenol

Electro-Fenton (EF) is a promising and green technology for environmental remediation. However, traditional EF often suffers from iron sludge production, leading to poor pH adaptation and secondary pollution. In this work, we synthesized a three-dimensional (3D) carbon nanotube architecture containing nitrogen and oxygen heteroatoms on carbon fibre paper (3D-NOCNTs/CFP) as an indirect catalyst for a metal-free EF process for the removal of 4-chlorophenol (4-CP). The dependence of the content and the type of the functional groups in the carbon plane on the pyrolysis temperature was studied through XPS measurements. This binder-free electrode has been identified as a bifunctional catalyst that can catalyze a high H2O2 yield process and a subsequent in-situ generation of ⋅OH via an O2 reduction reaction (ORR). Thus the generated ⋅OH radicals can directly participate in the oxidative degradation of 4-CP and the utilization of iron can be avoided in the EF process. The optimized electrode could remove 99.3 % 4-CP in 120 min and exhibits a broad suitability upon pH, an excellent capability, and a prominent stability for the degradation of 4-CP. The mechanism was explained by density function theory (DFT) calculations and the controlled experiments. Such a metal-free EF process features a promising green technology for the oxidative degradation of organic pollutants.

Development of emphatic catalysts for waste water remediation via synchronized free radical and non-free radical routes with composites of strontium hexaferrite, graphene and multi-walled carbon nanotubes

Magnetic nanoparticles have shown exceptional potential in catalysis, however, their tendency to agglomerate has confined their use. The present work encompasses synthesis of eco-friendly and magnetic retrievable catalysts with different fractions of reduced graphene oxide (rGO) and multiwalled carbon nanotubes (MWCNT) as support for strontium hexaferrite (SrFe12O19) for the oxidative degradation of organic pollutants. The morphological, structural and magnetic properties of composites were estimated via PXRD, FT-IR, VSM, FE-SEM, HR-TEM, XPS and BET. The crystallite size decreased from 41.46 nm for SrFe12O19 to 35.85 nm and 33 nm for composites with 20% rGO and MWCNTs, respectively while the surface area increased substantially from 88.1 m2/g for SrFe12O19 to 118.4 and 131.3 m2/g. Further, the composites were employed as catalysts for the oxidative degradation of selected antibiotics and colourant via stimulation of two different oxidants, potassium peroxymonosulphate (PMS) and hydrogen peroxide (H2O2). The degradation followed pseudo first order kinetics with rate constant values increasing with rGO and MWCNT content. The increase in catalyst effectiveness can be ascribed to the synergistic interactions between rGO or MWCNT and SrFe12O19, which provided larger specific surface areas for adsorption and augmented number of catalytically active sites. Systematic chemical quenching studies unveiled a combined role of radical and non-radical species in oxidative degradation of pollutants. Moreover, the synthesized composites exhibited excellent recyclability upto four cycles forming the basis for their utilization as industrial catalysts.

Synthesis and characterization of a new polyoxometalate nanocluster containing Mo and V as an environmentally green catalyst for oxidative degradation of organic pollutants from aquatic environments

AbstractA water‐insoluble Keggin‐type polyoxomolybdovanadate nanocluster, (Et4N)4[VMo12O40]·MeCN (1) was synthesized and crystallized in acetonitrile. The catalyst was characterized by X‐ray crystallography, UV–Vis, thermogravimetric analysis (TGA), cyclic voltammetry (CV), and FT‐IR techniques. Degradation of organic dyes, Amido black 10B (AB10B) and Methylene blue (MB) was investigated by 1/H2O2 system at room temperature and the influence of different conditions on the decomposition of AB10B and MB dyes such as catalyst dosage, oxidant concentration, pH, radical scavengers, and reusability of 1 were studied.

Degradation of organic pollutants in hazardous spent sulfuric acid by catalytic oxidation reaction with agricultural waste-derived catalyst

The discharge of spent sulfuric acid generates significant toxic wastes and poses serious hazards to the environment. The effective treatment of spent sulfuric acid remains a great challenge because conventional thermochemical pyrolysis is limited by energy-intensive processing, high equipment investment, and severe equipment corrosion. In this study, we propose an energy-efficient and moderate catalytic oxidation reaction to treat spent sulfuric acid. During the catalytic oxidation reaction, the organic pollutants, especially refractory acid-soluble oil (ASO), in the conversion of spent sulfuric acid and ammonia wastewater were oxidized and degraded into CO2, H2O, and inorganic structures with H2O2 as the oxidant and ozone-treated activated carbon (OAC), derived from coconut shells, as a catalyst. The catalytic activity of OAC enhanced the degradation efficiency of organic pollutants under mild conditions, which was ascribed to the abundant acidic functional groups, and the anchored metal ions on the OAC promoted the generation of highly reactive radicals. The purified (NH4)2SO4 solution with an ASO removal of 96.4% and total organic carbon (TOC) removal of ~92% under the optimum conditions was used to prepare the qualified (NH4)2SO4 product. This work demonstrates the effective utilization of spent sulfuric acid and a cost-effective route to prepare catalysts from agricultural waste for the oxidative degradation of organic pollutants.

Synergistic effects for boosted persulfate activation in a designed Fe–Cu dual-atom site catalyst

Advanced oxidation processes (AOPs) are promising ways for oxidative degradation of organic pollutants. Atom-dispersed transition metal–nitrogen–carbon (M–N–C) materials exhibit excellent efficiency in activating peroxide bonds and have been extensively pursued for environmental remediation. However, M–N–C with single atoms suffer from intrinsic performance limit of complicated catalytic reactions due to structural simplicity and lack of synergistic active sites. Herein, derived from Fe/Cu–coordinated zeolitic imidazolate frameworks with molecular-scale cages, a well–designed catalyst featuring Fe–Cu dual–metal sites coordinated with N–doped carbon (Fe/Cu–N–C) was fabricated. Compared to the single-atom iron catalyst (Fe–N–C), Fe/Cu–N–C significantly enhanced the chloramphenicol removal rate from 0.073 to 0.093 min−1 due to the synergistic effects of Fe–Cu dual active site. Furthermore, Fe/Cu–N–C exhibits fantastic reactivity for peroxydisulfate (PDS) activation in a wide pH range (3.1 – 10.3). Density functional theory calculations revealed that Fe/Cu–N is the major active site, where electrons transfer from Cu to Fe ensure the low-valence state of Fe for catalytic oxidation. Besides, the optimization of adjacent Cu–N sites improves the bonding orbital distribution of Fe 3d orbitals and promotes the adsorption and cracking of PDS. These findings reveal the cooperative mechanism of Fe–Cu dual–atom site on PDS activation and develop a promising platform toward environmental purification.

Does Tert-Butyl Alcohol Really Terminate the Oxidative Activity of •OH in Inorganic Redox Chemistry?

The hydroxyl radical, •OH, is one of the most reactive free radicals and plays significant roles in the oxidative degradation of organic pollutants and the electron transfer of inorganic ions in natural and engineered environmental processes. To quantitatively determine the contribution of •OH to oxidative reactions, a specific scavenger, such as tert-butyl alcohol (TBA), is usually added to eliminate •OH effects. Although TBA is commonly assumed to transform •OH into oxidatively inert products, this study demonstrates that utilizing TBA as an •OH scavenger generates the secondary peroxyl radical (ROO•), influencing the oxidation of transition metals, such as Mn. Although ROO• is less reactive than •OH, it has an extended half-life and a longer diffusion distance that enables more redox reactions, such as the oxidation of Mn2+(aq) to MnIV oxide solids. In addition to promoting Mn2+(aq) oxidation kinetics, TBA can also affect the crystalline phases, oxidation states, and morphologies of Mn oxide solids. Thus, the oxidative roles of •OH in aqueous redox reactions cannot be examined simply by adding TBA: the effects of secondary ROO• must also be considered. This study urges a closer look at the potential formation of secondary radicals during scavenged oxidative reactions in environmental systems.

Heterogeneous Fenton Degradation of Organic Pollutants in Water Enhanced by Combining Iron-type Layered Double Hydroxide and Sulfate.

Water pollution derived from organic pollutants is one of the global environmental problems. The Fenton reaction using Fe2+ as a homogeneous catalyst has been known as one of clean methods for oxidative degradation of organic pollutants. Here, a layered double hydroxide (Fe2+ Al3+ -LDH) containing Fe2+ and Al3+ in the structure was used to develop a "heterogeneous" Fenton catalyst capable of mineralizing organic pollutants. We found that sulfate ion (SO4 2- ) immobilized on the Fe2+ Al3+ -LDH significantly facilitated oxidative degradation (mineralization) of phenol as a model compound of water pollutants to carbon dioxide (CO2 ) in a heterogeneous Fenton process. The phenol conversion and mineralization efficiency to CO2 reached >99% and ca. 50%, respectively, even with a reaction time of only 60 min.

Boosting the activation of molecular oxygen and the degradation of tetracycline over high loading Ag single atomic catalyst

Photocatalytic activation of molecular oxygen (O2) is a promising way in oxidative degradation of organic pollutants. However, it suffers from low efficiency mainly due to the limited active sites for O2 activation over traditional photocatalysts. Therefore, we established a single atomic Ag-g-C3N4 (SAACN) catalyst with 10 wt% loading of Ag single sites for boosting the O2 activation during the degradation of tetracycline (TC), and 10 wt% loading of nanoparticle Ag-g-C3N4 (NPACN) was studied as a comparison. When using SAACN, the accumulative concentration of superoxide (•O2−), hydroxyl radical (•OH), singlet oxygen (1O2) reached up to 0.66, 0.19, 0.33 mmol L−1h−1, respectively, within 120 min, 11.7, 5.7 and 4.9 times compared with those using NPACN, representing 17.24% of dissolved O2 was converted to reactive oxygen species (ROS). When additionally feeding air or O2, the accumulative concentrations of •O2−, •OH, 1O2 were even higher (air: 4.21, 0.97, 2.02 mmol L−1 h−1; O2: 17.13, 1.32, 9.00 mmol L−1 h−1). The rate constants (k) for degrading the TC were 0.0409 min−1 over SAACN and 0.00880 min−1 over NPACN, respectively (mineralization rate: 95.7% vs. 59.9% after 3 h of degradation). Moreover, the degradation ability of SAACN did not decrease in a wide range of pH value (4–10) or under low temperature (10 °C). Besides the high exposure of Ag single sites, other advances of SAACN were: 1(O2 was more energetic favorable to adsorb on single atomic Ag sites; 2) Positive Ag single sites were easier to obtain the electrons from the surrounding N atoms, and facilitated electron transfer towards adsorbed O2.

Current analytical methods for the determination of persulfate in aqueous solutions: A historical review

• The methods for the determination of persulfate are systematically reviewed. • The advantages and limitations of each method in practice are analyzed. • Fluorescence method is suitable for measuring PMS in colored samples. • UV–vis spectrophotometry can be chosen for colorless samples. • Titration is the most recommended method if no lab equipments are available. Persulfate (peroxymonosulfate or peroxydisulfate) ions, as strong oxidants, have a broad application in the field of advanced oxidation processes (AOPs) for oxidative degradation of organic pollutants in soil and contaminated water. Persulfate concentration is an important operational parameter in persulfate degradation of organic pollutants based on SO 4 •− -AOPs. At present, the analytical methods used for quantification of persulfate mainly include traditional titration, polarography, electrochemiluminescence, electrochemical methods, spectrometry and chromatography. These methods vary in their limit of detection (LOD), execution time, operational difficulty, accuracy and sensitivity. The traditional methods are cheap and easy to operate, but the poor sensitivity and the high LOD limit its application. Electrochemiluminescence methods are highly sensitive with low detection limit, but requires rather specialized instruments. Electrochemical methods are repaid and have high sensitivity, low LOD and wide detection range, but relatively large reagent volume is needed in the determination process. Spectrophotometry has high accuracy with low consumption rate of sample and reagents, but it is susceptible to colored substances. Ion chromatography has the advantages of high sensitivity, less reagent consumption and simultaneous detection of multiple ions, but no advantage in detection time and LOD. This review presents the principles, merits and demerits of various existing analytical methods for persulfate determination, and discusses the limitations and applicability of various methods. This review is expected to provide some references for the establishment of novel detection methods for persulfate in the future.

Metal-Organic frameworks-derived multifunctional carbon encapsulated metallic nanocatalysts for catalytic peroxymonosulfate activation and electrochemical hydrogen generation

Synthesis of high-efficiency metal catalysts and their application in catalyzing critical chemical processes holds the key to the sustainable supply of water and energy. However, reaction-induced atomistic modifications of nanoclusters often result in reduced stability and efficacy. Herein, we report a highly active and multifunctional transition metal nanocatalysts encapsulated in porous carbon network (M@C where M = Cu, Ni, Fe, Co) prepared by leveraging the sacrificial templating properties of metal-organic frameworks (MOFs). The as-synthesized M@C nanocatalysts were employed for oxidative degradation of organic pollutants and electrocatalytic hydrogen generation. Fenton like catalytic studies revealed that the nanocatalysts were highly active and reusable following the order of Co@C > Fe@C > Cu@C > Ni@C. On the other hand, Ni@C electrocatalyst displayed superior activity towards hydrogen evolution reaction as compared to others, delivering a low onset potential of 61 mV, Tafel slope of 82 mV/dec and an overpotential of 286 mV at 10 mA‧cm−2. The activity was essentially unchanged even after 500 cycles, suggesting the long‐term stability under acidic conditions. The impressive multifunctional catalytic performances of M@C nanocatalysts are attributed to their unique porous carbon matrix doped by transition metal nanoparticles which provide a large number of interconnected catalytically active sites.