Hunan University of Science & Technology

Bismuth vanadate (BiVO 4 ) is regarded as a promising photoanode for photoelectrochemical (PEC) water splitting. Despite its advantage in band gap and visible-light response, the BiVO 4 exhibits an unsatisfactory achieving water splitting due to severe charge recombination. Herein, we elucidate an innovative approach involving the incorporation of single Ru atom with a CoFe-LDH cocatalyst (Ru 0.51 -CoFe-LDH) and integrating it onto the BiVO 4 semiconductor substrate. The resulting Ru 0.51 -CoFe-LDH/BiVO 4 photoanode film demonstrates commendable charge injection efficiency (76%) and charge collection efficiency (100%). Interestingly, the yield of hydrogen and oxygen increases linearly at a stoichiometric ratio of about 2:1, reaching 158.6 and 67.4 μmol after 140 min of irradiation, respectively. According to experimental characterization and density functional theory calculation, this remarkable performance results from single Ru atoms triggering the electron rearrangement of Ru 0.51 -CoFe-LDH to engineer active sites and optimize interfacial energetics. Additionally, the negative shift of Ru 0.51 -CoFe-LDH band edge gives rise to more conspicuous band bending of the n–n junction formed with BiVO 4 , expediting the separation and transfer of photogenerated electron–hole pairs at the interface. This work furnishes a new preparation perspective for PEC water splitting systems to construct single atoms in the semiconductor substrate.

Single-atom catalysts (SACs) are known for their exceptional catalytic efficiency but suffer from structural rigidity, limiting their adaptability in biological environments. Here, we present a hemoglobin-based gadolinium single-atom catalyst (Hb-Gd SAC), in which Gd atoms are site-specifically anchored adjacent to the native heme-Fe center via biomimetic coordination. Leveraging the intrinsic flexibility of the protein scaffold, the system exhibits pH- and conformation-gated switching between two distinct enzymatic modes: peroxidase-like (POD-like) activity under acidic conditions and laccase-like activity at neutral pH. These catalytic modes are mechanistically decoupled-global protein conformation governs POD activity, while localized Gd coordination drives laccase-like function. Allosteric regulation by tartaric acid further fine-tunes this behavior, significantly enhancing performance beyond that of natural horseradish peroxidase. This dual-mode catalysis supports programmable biosensing: POD mode enables detection of thiols and acetylcholinesterase activity, while the laccase mode selectively targets dopamine. Such multimodal detection is particularly relevant for neurodegenerative disease diagnostics, exemplified by Parkinson's disease, where simultaneous monitoring of oxidative stress, cholinergic dysfunction, and dopaminergic signaling is essential. Our findings introduce a reconfigurable SAC platform that couples atomic precision with biomolecular dynamics, advancing the frontier of intelligent catalysis and adaptive biosensing technologies.

Fatty acids play an important role in regulating gluconeogenesis through the metabolite acetyl-CoA, however, the underlying mechanisms on how fatty acid oxidation provides acetyl-CoA for the stimulation of pyruvate carboxylase and gluconeogenesis are not fully demonstrated. As a fatty acid β-oxidation system exists in peroxisomes and the acetyl-CoA derived from peroxisomal β-oxidation can be transported into mitochondria through the intermediate acetyl-carnitine, we hypothesize that this β-oxidation system might play a role in regulating pyruvate carboxylase and gluconeogenesis. The study demonstrates a mechanism by which fatty acids activate pyruvate carboxylase through the acetyl-CoA derived from peroxisomal β-oxidation. Induction of peroxisomal fatty acid β-oxidation results in excessive generation of acetyl-carnitine, which significantly elevates liver acetyl-CoA level and stimulates pyruvate carboxylase and gluconeogenesis in fasting mice. Specific inhibition of peroxisomal β-oxidation suppresses glucose production and lowers fasting glucose by reducing acetyl-CoA generation in the liver of diabetic mice. It is proposed that induction of peroxisomal β-oxidation serves as a pathogenic mechanism for fatty acids induced hyperactivation of pyruvate carboxylase and gluconeogenesis and targeting peroxisomal β-oxidation might be a potential pathway in treating diabetes through reducing acetyl-CoA generation and suppressing gluconeogenesis.