# One-Step Anodic Synthesis of Gd-Doped TiO2 Nanotubes for Enhanced Photocatalysis

## TL;DR

A new method creates Gd-doped TiO2 nanotubes that work better for photocatalysis, breaking down pollutants more efficiently under visible light.

## Contribution

A one-step anodization method enables uniform Gd doping in TiO2 nanotubes, improving photocatalytic efficiency and simplifying synthesis.

## Key findings

- Gd-doped TiO2 nanotubes degrade 90% of methylene blue in 60 minutes, 50% more efficient than undoped TiO2.
- Gd doping narrows the bandgap of TiO2 from 2.89 eV to 2.46 eV, enhancing visible-light absorption beyond 500 nm.
- The one-step method reduces processing steps by over 60% compared to traditional multi-step approaches.

## Abstract

What are the main findings?
A one-step in situ anodization method successfully fabricates Gd-doped TiO2 nanotubes with uniform dopant distribution.Gd doping narrows TiO2’s bandgap to 2.46 eV, extending visible-light absorption beyond 500 nm.The Gd-TiO2 nanotubes degrade 90% methylene blue in 60 min, 50% more efficient than undoped TiO2.

A one-step in situ anodization method successfully fabricates Gd-doped TiO2 nanotubes with uniform dopant distribution.

Gd doping narrows TiO2’s bandgap to 2.46 eV, extending visible-light absorption beyond 500 nm.

The Gd-TiO2 nanotubes degrade 90% methylene blue in 60 min, 50% more efficient than undoped TiO2.

What are the implications of the main findings?
Simplifies the synthesis of rare-earth-doped TiO2, reducing costs.Enhances solar energy utilization of TiO2-based photocatalysts for broader environmental remediation applications.Provides insights into bandgap engineering via rare earth doping for designing high-performance photocatalysts.

Simplifies the synthesis of rare-earth-doped TiO2, reducing costs.

Enhances solar energy utilization of TiO2-based photocatalysts for broader environmental remediation applications.

Provides insights into bandgap engineering via rare earth doping for designing high-performance photocatalysts.

Traditional methods for preparing rare-earth-doped TiO2 nanotubes are multi-step and often result in uneven dopant distribution, while pure TiO2 is limited by its wide bandgap and rapid charge recombination. In this study, a one-step in situ synchronous anodization strategy is developed to fabricate gadolinium (Gd)-doped TiO2 nanotube arrays directly on a titanium substrate. By adding gadolinium nitrate to an ethylene glycol–NH4F electrolyte, Gd incorporation and nanotube growth are achieved simultaneously, reducing the processing steps by over 60%. The obtained Gd–TiO2 nanotubes exhibit extended visible-light absorption with an edge beyond 500 nm and show a methylene blue degradation efficiency of 90% within 60 min, which is 50% higher than that of undoped TiO2. Scavenger experiments reveal that ·OH radicals play the predominant role in the photocatalytic process. First-principles calculations further confirm significant bandgap narrowing from 2.89 eV to 2.46 eV after Gd doping. This work provides a simple, efficient, and scalable synthesis route for high-performance TiO2-based photocatalysts with enhanced solar-driven activity.